31280857813 has 4 divisors (see below), whose sum is σ = 31294806048. Its totient is φ = 31266909580.

The previous prime is 31280857723. The next prime is 31280857819. The reversal of 31280857813 is 31875808213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31280857813 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 (31280857819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6970753 + ... + 6975238.

It is an arithmetic number, because the mean of its divisors is an integer number (7823701512).

Almost surely, 2^31280857813 is an apocalyptic number.

It is an amenable number.

31280857813 is a deficient number, since it is larger than the sum of its proper divisors (13948235).

31280857813 is a wasteful number, since it uses less digits than its factorization.

31280857813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13948234.

The product of its (nonzero) digits is 322560, while the sum is 46.

The spelling of 31280857813 in words is "thirty-one billion, two hundred eighty million, eight hundred fifty-seven thousand, eight hundred thirteen".