20564990 has 16 divisors (see below), whose sum is σ = 38626848. Its totient is φ = 7868256.

The previous prime is 20564989. The next prime is 20565001. The reversal of 20564990 is 9946502.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20564990.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44477 + ... + 44936.

It is an arithmetic number, because the mean of its divisors is an integer number (2414178).

Almost surely, 2^20564990 is an apocalyptic number.

20564990 is a deficient number, since it is larger than the sum of its proper divisors (18061858).

20564990 is a wasteful number, since it uses less digits than its factorization.

20564990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89443.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 20564990 is about 4534.8638347805. The cubic root of 20564990 is about 273.9740949100.

The spelling of 20564990 in words is "twenty million, five hundred sixty-four thousand, nine hundred ninety".