31000872 has 128 divisors (see below), whose sum is σ = 94556160. Its totient is φ = 8279040.

The previous prime is 31000859. The next prime is 31000873. The reversal of 31000872 is 27800013.

It is a super-2 number, since 2×31000872² = 1922108129520768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (31000873) 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, 274288 + ... + 274400.

It is an arithmetic number, because the mean of its divisors is an integer number (738720).

Almost surely, 2^31000872 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 31000872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47278080).

31000872 is an abundant number, since it is smaller than the sum of its proper divisors (63555288).

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

31000872 is a wasteful number, since it uses less digits than its factorization.

31000872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 219 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 31000872 is about 5567.8426701910. The cubic root of 31000872 is about 314.1410106781.

Adding to 31000872 its reverse (27800013), we get a palindrome (58800885).

The spelling of 31000872 in words is "thirty-one million, eight hundred seventy-two", and thus it is an aban number.