20664631808 has 30 divisors (see below), whose sum is σ = 41295403149. Its totient is φ = 10330689536.

The previous prime is 20664631807. The next prime is 20664631853. The reversal of 20664631808 is 80813646602.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 20630151424 + 34480384 = 143632^2 + 5872^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=101648.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20664631807) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3249560 + ... + 3255912.

Almost surely, 2^20664631808 is an apocalyptic number.

It is an amenable number.

20664631808 is a deficient number, since it is larger than the sum of its proper divisors (20630771341).

20664631808 is an frugal number, since it uses more digits than its factorization.

20664631808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12724 (or 6355 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 44.

The spelling of 20664631808 in words is "twenty billion, six hundred sixty-four million, six hundred thirty-one thousand, eight hundred eight".