20640564417 has 24 divisors (see below), whose sum is σ = 30614586912. Its totient is φ = 12358698880.

The previous prime is 20640564407. The next prime is 20640564419. The reversal of 20640564417 is 71446504602.

It is not a de Polignac number, because 20640564417 - 2⁶ = 20640564353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20640564419) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 312408 + ... + 372665.

It is an arithmetic number, because the mean of its divisors is an integer number (1275607788).

Almost surely, 2^20640564417 is an apocalyptic number.

It is an amenable number.

20640564417 is a deficient number, since it is larger than the sum of its proper divisors (9974022495).

20640564417 is a wasteful number, since it uses less digits than its factorization.

20640564417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685181 (or 685170 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 39.

The spelling of 20640564417 in words is "twenty billion, six hundred forty million, five hundred sixty-four thousand, four hundred seventeen".