20320637257 has 2 divisors, whose sum is σ = 20320637258. Its totient is φ = 20320637256.

The previous prime is 20320637191. The next prime is 20320637273. The reversal of 20320637257 is 75273602302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13231670841 + 7088966416 = 115029^2 + 84196^2 .

It is a cyclic number.

It is not a de Polignac number, because 20320637257 - 2²⁷ = 20186419529 is a prime.

It is not a weakly prime, because it can be changed into another prime (20320607257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160318628 + 10160318629.

It is an arithmetic number, because the mean of its divisors is an integer number (10160318629).

Almost surely, 2^20320637257 is an apocalyptic number.

It is an amenable number.

20320637257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20320637257 is an equidigital number, since it uses as much as digits as its factorization.

20320637257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 37.

The spelling of 20320637257 in words is "twenty billion, three hundred twenty million, six hundred thirty-seven thousand, two hundred fifty-seven".