31287021312 has 288 divisors, whose sum is σ = 88611618816. Its totient is φ = 9786470400.

The previous prime is 31287021307. The next prime is 31287021319. The reversal of 31287021312 is 21312078213.

It is a self number, because there is not a number n which added to its sum of digits gives 31287021312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31287021319) 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, 140300433 + ... + 140300655.

It is an arithmetic number, because the mean of its divisors is an integer number (307679232).

Almost surely, 2^31287021312 is an apocalyptic number.

31287021312 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31287021312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44305809408).

31287021312 is an abundant number, since it is smaller than the sum of its proper divisors (57324597504).

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

31287021312 is a wasteful number, since it uses less digits than its factorization.

31287021312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

Adding to 31287021312 its reverse (21312078213), we get a palindrome (52599099525).

The spelling of 31287021312 in words is "thirty-one billion, two hundred eighty-seven million, twenty-one thousand, three hundred twelve".