21242312111257 has 2 divisors, whose sum is σ = 21242312111258. Its totient is φ = 21242312111256.

The previous prime is 21242312111221. The next prime is 21242312111269. The reversal of 21242312111257 is 75211121324212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20578235432976 + 664076678281 = 4536324^2 + 814909^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21242312111257 is a prime.

It is a super-2 number, since 2×21242312111257² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21242312111357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621156055628 + 10621156055629.

It is an arithmetic number, because the mean of its divisors is an integer number (10621156055629).

Almost surely, 2^{21242312111257} is an apocalyptic number.

It is an amenable number.

21242312111257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21242312111257 is an equidigital number, since it uses as much as digits as its factorization.

21242312111257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 34.

Adding to 21242312111257 its reverse (75211121324212), we get a palindrome (96453433435469).

The spelling of 21242312111257 in words is "twenty-one trillion, two hundred forty-two billion, three hundred twelve million, one hundred eleven thousand, two hundred fifty-seven".