20664636660 has 72 divisors (see below), whose sum is σ = 62697922560. Its totient is φ = 5509234368.

The previous prime is 20664636631. The next prime is 20664636667. The reversal of 20664636660 is 6663646602.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20664636667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 895629 + ... + 918411.

It is an arithmetic number, because the mean of its divisors is an integer number (870804480).

Almost surely, 2^20664636660 is an apocalyptic number.

20664636660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20664636660 is an abundant number, since it is smaller than the sum of its proper divisors (42033285900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20664636660 is a wasteful number, since it uses less digits than its factorization.

20664636660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27837 (or 27832 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 45.

The spelling of 20664636660 in words is "twenty billion, six hundred sixty-four million, six hundred thirty-six thousand, six hundred sixty".