20664810645 has 48 divisors (see below), whose sum is σ = 34519222080. Its totient is φ = 10555038720.

The previous prime is 20664810559. The next prime is 20664810679. The reversal of 20664810645 is 54601846602.

It is not a de Polignac number, because 20664810645 - 2²⁰ = 20663762069 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20664810597 and 20664810606.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1390866 + ... + 1405644.

It is an arithmetic number, because the mean of its divisors is an integer number (719150460).

Almost surely, 2^20664810645 is an apocalyptic number.

It is an amenable number.

20664810645 is a deficient number, since it is larger than the sum of its proper divisors (13854411435).

20664810645 is a wasteful number, since it uses less digits than its factorization.

20664810645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14946 (or 14915 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 42.

The spelling of 20664810645 in words is "twenty billion, six hundred sixty-four million, eight hundred ten thousand, six hundred forty-five".