31388563397 has 4 divisors (see below), whose sum is σ = 32154138156. Its totient is φ = 30622988640.

The previous prime is 31388563333. The next prime is 31388563403. The reversal of 31388563397 is 79336588313.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19101727681 + 12286835716 = 138209^2 + 110846^2 .

It is a cyclic number.

It is not a de Polignac number, because 31388563397 - 2⁶ = 31388563333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31388563307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 382787318 + ... + 382787399.

It is an arithmetic number, because the mean of its divisors is an integer number (8038534539).

Almost surely, 2^31388563397 is an apocalyptic number.

It is an amenable number.

31388563397 is a deficient number, since it is larger than the sum of its proper divisors (765574759).

31388563397 is an equidigital number, since it uses as much as digits as its factorization.

31388563397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765574758.

The product of its digits is 9797760, while the sum is 56.

The spelling of 31388563397 in words is "thirty-one billion, three hundred eighty-eight million, five hundred sixty-three thousand, three hundred ninety-seven".