31791959621 has 4 divisors (see below), whose sum is σ = 31792478412. Its totient is φ = 31791440832.

The previous prime is 31791959569. The next prime is 31791959623. The reversal of 31791959621 is 12695919713.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12695919713 = 67 ⋅189491339.

It can be written as a sum of positive squares in 2 ways, for example, as 11080720225 + 20711239396 = 105265^2 + 143914^2 .

It is a cyclic number.

It is not a de Polignac number, because 31791959621 - 2²⁶ = 31724850757 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 (31791959623) 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, 152900 + ... + 294893.

It is an arithmetic number, because the mean of its divisors is an integer number (7948119603).

Almost surely, 2^31791959621 is an apocalyptic number.

It is an amenable number.

31791959621 is a deficient number, since it is larger than the sum of its proper divisors (518791).

31791959621 is an equidigital number, since it uses as much as digits as its factorization.

31791959621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518790.

The product of its digits is 918540, while the sum is 53.

The spelling of 31791959621 in words is "thirty-one billion, seven hundred ninety-one million, nine hundred fifty-nine thousand, six hundred twenty-one".