31000420 has 96 divisors (see below), whose sum is σ = 75841920. Its totient is φ = 10536960.

The previous prime is 31000397. The next prime is 31000421. The reversal of 31000420 is 2400013.

31000420 = T₅₅ + T₅₆ + ... + T₅₇₀.

It is a super-2 number, since 2×31000420² = 1922052080352800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 31000397 and 31000406.

It is not an unprimeable number, because it can be changed into a prime (31000421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 274284 + ... + 274396.

It is an arithmetic number, because the mean of its divisors is an integer number (790020).

Almost surely, 2^31000420 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 31000420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37920960).

31000420 is an abundant number, since it is smaller than the sum of its proper divisors (44841500).

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

31000420 is a wasteful number, since it uses less digits than its factorization.

31000420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 203 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 31000420 is about 5567.8020798157. The cubic root of 31000420 is about 314.1394839208.

Adding to 31000420 its reverse (2400013), we get a palindrome (33400433).

The spelling of 31000420 in words is "thirty-one million, four hundred twenty", and thus it is an aban number.