20564919 has 12 divisors (see below), whose sum is σ = 29788200. Its totient is φ = 13671504.

The previous prime is 20564909. The next prime is 20564923. The reversal of 20564919 is 91946502.

20564919 is a `hidden beast` number, since 2 + 0 + 5 + 649 + 1 + 9 = 666.

It is not a de Polignac number, because 20564919 - 2¹⁶ = 20499383 is a prime.

It is a super-2 number, since 2×20564919² = 845831786953122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 397 + ... + 6425.

It is an arithmetic number, because the mean of its divisors is an integer number (2482350).

Almost surely, 2^20564919 is an apocalyptic number.

20564919 is a deficient number, since it is larger than the sum of its proper divisors (9223281).

20564919 is a wasteful number, since it uses less digits than its factorization.

20564919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6414 (or 6411 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 20564919 is about 4534.8560065343. The cubic root of 20564919 is about 273.9737796139.

The spelling of 20564919 in words is "twenty million, five hundred sixty-four thousand, nine hundred nineteen".