20199999957857 has 2 divisors, whose sum is σ = 20199999957858. Its totient is φ = 20199999957856.

The previous prime is 20199999957833. The next prime is 20199999957869. The reversal of 20199999957857 is 75875999999102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19528347589921 + 671652367936 = 4419089^2 + 819544^2 .

It is a cyclic number.

It is not a de Polignac number, because 20199999957857 - 2¹² = 20199999953761 is a prime.

It is not a weakly prime, because it can be changed into another prime (20199999927857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10099999978928 + 10099999978929.

It is an arithmetic number, because the mean of its divisors is an integer number (10099999978929).

Almost surely, 2^{20199999957857} is an apocalyptic number.

It is an amenable number.

20199999957857 is a deficient number, since it is larger than the sum of its proper divisors (1).

20199999957857 is an equidigital number, since it uses as much as digits as its factorization.

20199999957857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10416243600, while the sum is 89.

The spelling of 20199999957857 in words is "twenty trillion, one hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred fifty-seven thousand, eight hundred fifty-seven".