31899388817 has 4 divisors (see below), whose sum is σ = 32336366820. Its totient is φ = 31462410816.

The previous prime is 31899388799. The next prime is 31899388841. The reversal of 31899388817 is 71888399813.

It is a happy number.

It is a Cunningham number, because it is equal to 178604²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 71888399813 = 34283 ⋅2096911.

It can be written as a sum of positive squares in 2 ways, for example, as 18107470096 + 13791918721 = 134564^2 + 117439^2 .

It is a cyclic number.

It is not a de Polignac number, because 31899388817 - 2⁸ = 31899388561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31899388877) 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, 218488892 + ... + 218489037.

It is an arithmetic number, because the mean of its divisors is an integer number (8084091705).

Almost surely, 2^31899388817 is an apocalyptic number.

It is an amenable number.

31899388817 is a deficient number, since it is larger than the sum of its proper divisors (436978003).

31899388817 is an equidigital number, since it uses as much as digits as its factorization.

31899388817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436978002.

The product of its digits is 20901888, while the sum is 65.

The spelling of 31899388817 in words is "thirty-one billion, eight hundred ninety-nine million, three hundred eighty-eight thousand, eight hundred seventeen".