31131220424 has 32 divisors (see below), whose sum is σ = 60068131200. Its totient is φ = 15118109760.

The previous prime is 31131220387. The next prime is 31131220447. The reversal of 31131220424 is 42402213113.

It is a self number, because there is not a number n which added to its sum of digits gives 31131220424.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266759 + ... + 365270.

It is an arithmetic number, because the mean of its divisors is an integer number (1877129100).

Almost surely, 2^31131220424 is an apocalyptic number.

It is an amenable number.

31131220424 is a deficient number, since it is larger than the sum of its proper divisors (28936910776).

31131220424 is a wasteful number, since it uses less digits than its factorization.

31131220424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632213 (or 632209 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 31131220424 its reverse (42402213113), we get a palindrome (73533433537).

The spelling of 31131220424 in words is "thirty-one billion, one hundred thirty-one million, two hundred twenty thousand, four hundred twenty-four".