31520406397 has 8 divisors (see below), whose sum is σ = 32555068344. Its totient is φ = 30502038528.

The previous prime is 31520406361. The next prime is 31520406427. The reversal of 31520406397 is 79360402513.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13843640281 + 17676766116 = 117659^2 + 132954^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31520406397 - 2¹⁵ = 31520373629 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 (31520406317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4069588 + ... + 4077325.

It is an arithmetic number, because the mean of its divisors is an integer number (4069383543).

Almost surely, 2^31520406397 is an apocalyptic number.

It is an amenable number.

31520406397 is a deficient number, since it is larger than the sum of its proper divisors (1034661947).

31520406397 is an equidigital number, since it uses as much as digits as its factorization.

31520406397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8147039.

The product of its (nonzero) digits is 136080, while the sum is 40.

The spelling of 31520406397 in words is "thirty-one billion, five hundred twenty million, four hundred six thousand, three hundred ninety-seven".