636213311957 has 2 divisors, whose sum is σ = 636213311958. Its totient is φ = 636213311956.

The previous prime is 636213311947. The next prime is 636213312019. The reversal of 636213311957 is 759113312636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 460316113156 + 175897198801 = 678466^2 + 419401^2 .

It is a cyclic number.

It is not a de Polignac number, because 636213311957 - 2²⁰ = 636212263381 is a prime.

It is a super-2 number, since 2×636213311957² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636213311927) 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, 318106655978 + 318106655979.

It is an arithmetic number, because the mean of its divisors is an integer number (318106655979).

Almost surely, 2^636213311957 is an apocalyptic number.

It is an amenable number.

636213311957 is a deficient number, since it is larger than the sum of its proper divisors (1).

636213311957 is an equidigital number, since it uses as much as digits as its factorization.

636213311957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 612360, while the sum is 47.

The spelling of 636213311957 in words is "six hundred thirty-six billion, two hundred thirteen million, three hundred eleven thousand, nine hundred fifty-seven".