20523990 has 32 divisors (see below), whose sum is σ = 51851520. Its totient is φ = 5184864.

The previous prime is 20523989. The next prime is 20524003. The reversal of 20523990 is 9932502.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 17434 + ... + 18573.

It is an arithmetic number, because the mean of its divisors is an integer number (1620360).

Almost surely, 2^20523990 is an apocalyptic number.

20523990 is an abundant number, since it is smaller than the sum of its proper divisors (31327530).

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

20523990 is a wasteful number, since it uses less digits than its factorization.

20523990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36036.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 20523990 is about 4530.3410467646. The cubic root of 20523990 is about 273.7919015946.

The spelling of 20523990 in words is "twenty million, five hundred twenty-three thousand, nine hundred ninety".