20564393 has 4 divisors (see below), whose sum is σ = 21273540. Its totient is φ = 19855248.

The previous prime is 20564389. The next prime is 20564399. The reversal of 20564393 is 39346502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6822544 + 13741849 = 2612^2 + 3707^2 .

It is a cyclic number.

It is not a de Polignac number, because 20564393 - 2² = 20564389 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20564399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354530 + ... + 354587.

It is an arithmetic number, because the mean of its divisors is an integer number (5318385).

Almost surely, 2^20564393 is an apocalyptic number.

It is an amenable number.

20564393 is a deficient number, since it is larger than the sum of its proper divisors (709147).

20564393 is an equidigital number, since it uses as much as digits as its factorization.

20564393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709146.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 20564393 is about 4534.7980109372. The cubic root of 20564393 is about 273.9714437357.

The spelling of 20564393 in words is "twenty million, five hundred sixty-four thousand, three hundred ninety-three".