20661805008 has 60 divisors (see below), whose sum is σ = 62272390180. Its totient is φ = 6357477888.

The previous prime is 20661805001. The next prime is 20661805019. The reversal of 20661805008 is 80050816602.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 996791184 + 19665013824 = 31572^2 + 140232^2 .

It is a super-2 number, since 2×20661805008² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20661805001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5516773 + ... + 5520516.

Almost surely, 2^20661805008 is an apocalyptic number.

It is an amenable number.

20661805008 is an abundant number, since it is smaller than the sum of its proper divisors (41610585172).

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

20661805008 is a wasteful number, since it uses less digits than its factorization.

20661805008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11037316 (or 11037307 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The spelling of 20661805008 in words is "twenty billion, six hundred sixty-one million, eight hundred five thousand, eight".