21311299951057 has 2 divisors, whose sum is σ = 21311299951058. Its totient is φ = 21311299951056.

The previous prime is 21311299951027. The next prime is 21311299951063. The reversal of 21311299951057 is 75015999211312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17692463350081 + 3618836600976 = 4206241^2 + 1902324^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21311299951057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311299950989 and 21311299951007.

It is not a weakly prime, because it can be changed into another prime (21311299951027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655649975528 + 10655649975529.

It is an arithmetic number, because the mean of its divisors is an integer number (10655649975529).

Almost surely, 2^{21311299951057} is an apocalyptic number.

It is an amenable number.

21311299951057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311299951057 is an equidigital number, since it uses as much as digits as its factorization.

21311299951057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1530900, while the sum is 55.

The spelling of 21311299951057 in words is "twenty-one trillion, three hundred eleven billion, two hundred ninety-nine million, nine hundred fifty-one thousand, fifty-seven".