21064364831 has 2 divisors, whose sum is σ = 21064364832. Its totient is φ = 21064364830.

The previous prime is 21064364779. The next prime is 21064364857. The reversal of 21064364831 is 13846346012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21064364831 - 2¹⁰ = 21064363807 is a prime.

It is a super-2 number, since 2×21064364831² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21064360831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532182415 + 10532182416.

It is an arithmetic number, because the mean of its divisors is an integer number (10532182416).

Almost surely, 2^21064364831 is an apocalyptic number.

21064364831 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064364831 is an equidigital number, since it uses as much as digits as its factorization.

21064364831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 82944, while the sum is 38.

The spelling of 21064364831 in words is "twenty-one billion, sixty-four million, three hundred sixty-four thousand, eight hundred thirty-one".