31851139212 has 72 divisors (see below), whose sum is σ = 84830054400. Its totient is φ = 10048766688.

The previous prime is 31851139189. The next prime is 31851139217. The reversal of 31851139212 is 21293115813.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (31851139217) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 722089 + ... + 764927.

It is an arithmetic number, because the mean of its divisors is an integer number (1178195200).

Almost surely, 2^31851139212 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 31851139212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42415027200).

31851139212 is an abundant number, since it is smaller than the sum of its proper divisors (52978915188).

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

31851139212 is a wasteful number, since it uses less digits than its factorization.

31851139212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43955 (or 43950 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The spelling of 31851139212 in words is "thirty-one billion, eight hundred fifty-one million, one hundred thirty-nine thousand, two hundred twelve".