31520431421387 has 2 divisors, whose sum is σ = 31520431421388. Its totient is φ = 31520431421386.

The previous prime is 31520431421363. The next prime is 31520431421471. The reversal of 31520431421387 is 78312413402513.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31520431421387 - 2²⁰ = 31520430372811 is a prime.

It is a super-2 number, since 2×31520431421387² (a number of 28 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31520431423387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15760215710693 + 15760215710694.

It is an arithmetic number, because the mean of its divisors is an integer number (15760215710694).

Almost surely, 2^{31520431421387} is an apocalyptic number.

31520431421387 is a deficient number, since it is larger than the sum of its proper divisors (1).

31520431421387 is an equidigital number, since it uses as much as digits as its factorization.

31520431421387 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 483840, while the sum is 44.

The spelling of 31520431421387 in words is "thirty-one trillion, five hundred twenty billion, four hundred thirty-one million, four hundred twenty-one thousand, three hundred eighty-seven".