31509828397 has 6 divisors (see below), whose sum is σ = 32939386382. Its totient is φ = 30139835352.

The previous prime is 31509828391. The next prime is 31509828439. The reversal of 31509828397 is 79382890513.

It can be written as a sum of positive squares in only one way, i.e., 26419576681 + 5090251716 = 162541^2 + 71346^2 .

It is a de Polignac number, because none of the positive numbers 2^k-31509828397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31509828391) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 29781918 + ... + 29782975.

Almost surely, 2^31509828397 is an apocalyptic number.

It is an amenable number.

31509828397 is a deficient number, since it is larger than the sum of its proper divisors (1429557985).

31509828397 is an equidigital number, since it uses as much as digits as its factorization.

31509828397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59564939 (or 59564916 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 31509828397 in words is "thirty-one billion, five hundred nine million, eight hundred twenty-eight thousand, three hundred ninety-seven".