20640821208 has 64 divisors (see below), whose sum is σ = 58993374720. Its totient is φ = 5895417600.

The previous prime is 20640821191. The next prime is 20640821213. The reversal of 20640821208 is 80212804602.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 530748 + ... + 568308.

It is an arithmetic number, because the mean of its divisors is an integer number (921771480).

Almost surely, 2^20640821208 is an apocalyptic number.

20640821208 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

20640821208 is an abundant number, since it is smaller than the sum of its proper divisors (38352553512).

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

20640821208 is a wasteful number, since it uses less digits than its factorization.

20640821208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40848 (or 40844 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 33.

The spelling of 20640821208 in words is "twenty billion, six hundred forty million, eight hundred twenty-one thousand, two hundred eight".