Search a number
-
+
31000000 = 265631
BaseRepresentation
bin111011001000…
…0010111000000
32011022222000011
41312100113000
530414000000
63024234304
7524332003
oct166202700
964288004
1031000000
1116553839
12a46b994
1365651c5
14418d53a
152ac52ba
hex1d905c0

31000000 has 98 divisors (see below), whose sum is σ = 79373984. Its totient is φ = 12000000.

The previous prime is 30999989. The next prime is 31000003. The reversal of 31000000 is 13.

Adding to 31000000 its reverse (13), we get a palindrome (31000013).

It is a happy number.

It is a super-2 number, since 2×310000002 = 1922000000000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (4).

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000003) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 999985 + ... + 1000015.

Almost surely, 231000000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39686992).

31000000 is an abundant number, since it is smaller than the sum of its proper divisors (48373984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31000000 is an frugal number, since it uses more digits than its factorization.

31000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 3, while the sum is 4.

The square root of 31000000 is about 5567.7643628300. The cubic root of 31000000 is about 314.1380652391.

The spelling of 31000000 in words is "thirty-one million", and thus it is an aban number and an uban number.

Divisors: 1 2 4 5 8 10 16 20 25 31 32 40 50 62 64 80 100 124 125 155 160 200 248 250 310 320 400 496 500 620 625 775 800 992 1000 1240 1250 1550 1600 1984 2000 2480 2500 3100 3125 3875 4000 4960 5000 6200 6250 7750 8000 9920 10000 12400 12500 15500 15625 19375 20000 24800 25000 31000 31250 38750 40000 49600 50000 62000 62500 77500 96875 100000 124000 125000 155000 193750 200000 248000 250000 310000 387500 484375 500000 620000 775000 968750 1000000 1240000 1550000 1937500 3100000 3875000 6200000 7750000 15500000 31000000