20320661057 has 2 divisors, whose sum is σ = 20320661058. Its totient is φ = 20320661056.

The previous prime is 20320661029. The next prime is 20320661071. The reversal of 20320661057 is 75016602302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11589814336 + 8730846721 = 107656^2 + 93439^2 .

It is a cyclic number.

It is not a de Polignac number, because 20320661057 - 2⁶ = 20320660993 is a prime.

It is not a weakly prime, because it can be changed into another prime (20320661027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160330528 + 10160330529.

It is an arithmetic number, because the mean of its divisors is an integer number (10160330529).

Almost surely, 2^20320661057 is an apocalyptic number.

It is an amenable number.

20320661057 is a deficient number, since it is larger than the sum of its proper divisors (1).

20320661057 is an equidigital number, since it uses as much as digits as its factorization.

20320661057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 32.

The spelling of 20320661057 in words is "twenty billion, three hundred twenty million, six hundred sixty-one thousand, fifty-seven".