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31000 = 235331
BaseRepresentation
bin111100100011000
31120112011
413210120
51443000
6355304
7156244
oct74430
946464
1031000
1121322
1215b34
1311158
14b424
1592ba
hex7918

31000 has 32 divisors (see below), whose sum is σ = 74880. Its totient is φ = 12000.

The previous prime is 30983. The next prime is 31013. The reversal of 31000 is 13.

Adding to 31000 its reverse (13), we get a palindrome (31013).

It is a happy number.

31000 is nontrivially palindromic in base 9.

It is a super-2 number, since 2×310002 = 1922000000, which contains 22 as substring.

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

31000 is an undulating number in base 9.

It is a plaindrome in base 13.

It is a nialpdrome in base 8 and base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 985 + ... + 1015.

It is an arithmetic number, because the mean of its divisors is an integer number (2340).

231000 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 31000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37440).

31000 is an abundant number, since it is smaller than the sum of its proper divisors (43880).

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

31000 is a wasteful number, since it uses less digits than its factorization.

31000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52 (or 38 counting only the distinct ones).

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

The square root of 31000 is about 176.0681686166. The cubic root of 31000 is about 31.4138065239.

The spelling of 31000 in words is "thirty-one thousand".