20857715057 has 2 divisors, whose sum is σ = 20857715058. Its totient is φ = 20857715056.

The previous prime is 20857715051. The next prime is 20857715077. The reversal of 20857715057 is 75051775802.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13603956496 + 7253758561 = 116636^2 + 85169^2 .

It is a cyclic number.

It is not a de Polignac number, because 20857715057 - 2⁴ = 20857715041 is a prime.

It is not a weakly prime, because it can be changed into another prime (20857715051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428857528 + 10428857529.

It is an arithmetic number, because the mean of its divisors is an integer number (10428857529).

Almost surely, 2^20857715057 is an apocalyptic number.

It is an amenable number.

20857715057 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857715057 is an equidigital number, since it uses as much as digits as its factorization.

20857715057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 686000, while the sum is 47.

The spelling of 20857715057 in words is "twenty billion, eight hundred fifty-seven million, seven hundred fifteen thousand, fifty-seven".