20998564 has 12 divisors (see below), whose sum is σ = 37073484. Its totient is φ = 10406144.

The previous prime is 20998531. The next prime is 20998583. The reversal of 20998564 is 46589902.

It can be written as a sum of positive squares in 2 ways, for example, as 7617600 + 13380964 = 2760^2 + 3658^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20998564.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22777 + ... + 23680.

It is an arithmetic number, because the mean of its divisors is an integer number (3089457).

Almost surely, 2^20998564 is an apocalyptic number.

It is an amenable number.

20998564 is a deficient number, since it is larger than the sum of its proper divisors (16074920).

20998564 is a wasteful number, since it uses less digits than its factorization.

20998564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46574 (or 46572 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 20998564 is about 4582.4190118321. The cubic root of 20998564 is about 275.8861288993.

The spelling of 20998564 in words is "twenty million, nine hundred ninety-eight thousand, five hundred sixty-four".