20910805920 has 72 divisors (see below), whose sum is σ = 71358130116. Its totient is φ = 5576214528.

The previous prime is 20910805913. The next prime is 20910805921. The reversal of 20910805920 is 2950801902.

It can be written as a sum of positive squares in 2 ways, for example, as 19891153296 + 1019652624 = 141036^2 + 31932^2 .

It is a tau number, because it is divible by the number of its divisors (72).

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

It is not an unprimeable number, because it can be changed into a prime (20910805921) 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, 7259257 + ... + 7262136.

Almost surely, 2^20910805920 is an apocalyptic number.

20910805920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20910805920 is an abundant number, since it is smaller than the sum of its proper divisors (50447324196).

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

20910805920 is a wasteful number, since it uses less digits than its factorization.

20910805920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14521414 (or 14521403 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The spelling of 20910805920 in words is "twenty billion, nine hundred ten million, eight hundred five thousand, nine hundred twenty".