20664501609 has 16 divisors (see below), whose sum is σ = 29109208320. Its totient is φ = 13018279680.

The previous prime is 20664501607. The next prime is 20664501679. The reversal of 20664501609 is 90610546602.

It is not a de Polignac number, because 20664501609 - 2¹ = 20664501607 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20664501601) 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 in 15 ways as a sum of consecutive naturals, for example, 2522752 + ... + 2530929.

It is an arithmetic number, because the mean of its divisors is an integer number (1819325520).

Almost surely, 2^20664501609 is an apocalyptic number.

20664501609 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20664501609 is a deficient number, since it is larger than the sum of its proper divisors (8444706711).

20664501609 is a wasteful number, since it uses less digits than its factorization.

20664501609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5053760.

The product of its (nonzero) digits is 77760, while the sum is 39.

The spelling of 20664501609 in words is "twenty billion, six hundred sixty-four million, five hundred one thousand, six hundred nine".