20580921921 has 64 divisors (see below), whose sum is σ = 32779468800. Its totient is φ = 11241524736.

The previous prime is 20580921919. The next prime is 20580921937. The reversal of 20580921921 is 12912908502.

It is not a de Polignac number, because 20580921921 - 2¹ = 20580921919 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20580921921.

It is not an unprimeable number, because it can be changed into a prime (20580921971) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14301520 + ... + 14302958.

It is an arithmetic number, because the mean of its divisors is an integer number (512179200).

Almost surely, 2^20580921921 is an apocalyptic number.

20580921921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20580921921 is a deficient number, since it is larger than the sum of its proper divisors (12198546879).

20580921921 is a wasteful number, since it uses less digits than its factorization.

20580921921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798.

The product of its (nonzero) digits is 25920, while the sum is 39.

The spelling of 20580921921 in words is "twenty billion, five hundred eighty million, nine hundred twenty-one thousand, nine hundred twenty-one".