21076864165 has 24 divisors (see below), whose sum is σ = 29427928992. Its totient is φ = 14449589280.

The previous prime is 21076864157. The next prime is 21076864169. The reversal of 21076864165 is 56146867012.

It is not a de Polignac number, because 21076864165 - 2³ = 21076864157 is a prime.

It is a super-2 number, since 2×21076864165² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21076864169) 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 in 23 ways as a sum of consecutive naturals, for example, 2202922 + ... + 2212468.

It is an arithmetic number, because the mean of its divisors is an integer number (1226163708).

Almost surely, 2^21076864165 is an apocalyptic number.

It is an amenable number.

21076864165 is a deficient number, since it is larger than the sum of its proper divisors (8351064827).

21076864165 is an equidigital number, since it uses as much as digits as its factorization.

21076864165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18577 (or 18570 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 46.

The spelling of 21076864165 in words is "twenty-one billion, seventy-six million, eight hundred sixty-four thousand, one hundred sixty-five".