20889855921 has 24 divisors (see below), whose sum is σ = 31144506912. Its totient is φ = 12351692800.

The previous prime is 20889855907. The next prime is 20889855941. The reversal of 20889855921 is 12955898802.

It is not a de Polignac number, because 20889855921 - 2²⁷ = 20755638193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20889855941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 132816 + ... + 243761.

It is an arithmetic number, because the mean of its divisors is an integer number (1297687788).

Almost surely, 2^20889855921 is an apocalyptic number.

It is an amenable number.

20889855921 is a deficient number, since it is larger than the sum of its proper divisors (10254650991).

20889855921 is a wasteful number, since it uses less digits than its factorization.

20889855921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376673 (or 376632 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 57.

The spelling of 20889855921 in words is "twenty billion, eight hundred eighty-nine million, eight hundred fifty-five thousand, nine hundred twenty-one".