31311128640 has 448 divisors, whose sum is σ = 112436379648. Its totient is φ = 7315660800.

The previous prime is 31311128621. The next prime is 31311128707. The reversal of 31311128640 is 4682111313.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 31311128598 and 31311128607.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 49621125 + ... + 49621755.

Almost surely, 2^31311128640 is an apocalyptic number.

31311128640 is a gapful number since it is divisible by the number (30) 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 31311128640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (56218189824).

31311128640 is an abundant number, since it is smaller than the sum of its proper divisors (81125251008).

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

31311128640 is a wasteful number, since it uses less digits than its factorization.

31311128640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826 (or 816 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

Adding to 31311128640 its reverse (4682111313), we get a palindrome (35993239953).

It can be divided in two parts, 31311 and 128640, that added together give a palindrome (159951).

The spelling of 31311128640 in words is "thirty-one billion, three hundred eleven million, one hundred twenty-eight thousand, six hundred forty".