20889990 has 48 divisors (see below), whose sum is σ = 59254416. Its totient is φ = 5064000.

The previous prime is 20889943. The next prime is 20890019. The reversal of 20889990 is 9998802.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9561 + ... + 11540.

It is an arithmetic number, because the mean of its divisors is an integer number (1234467).

Almost surely, 2^20889990 is an apocalyptic number.

20889990 is an abundant number, since it is smaller than the sum of its proper divisors (38364426).

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

20889990 is a wasteful number, since it uses less digits than its factorization.

20889990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21125 (or 21122 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 20889990 is about 4570.5568588521. The cubic root of 20889990 is about 275.4098132231.

The spelling of 20889990 in words is "twenty million, eight hundred eighty-nine thousand, nine hundred ninety".