20564431 has 2 divisors, whose sum is σ = 20564432. Its totient is φ = 20564430.

The previous prime is 20564399. The next prime is 20564459. The reversal of 20564431 is 13446502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20564431 - 2⁵ = 20564399 is a prime.

It is a super-2 number, since 2×20564431² = 845791644707522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20564396 and 20564405.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20564491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10282215 + 10282216.

It is an arithmetic number, because the mean of its divisors is an integer number (10282216).

Almost surely, 2^20564431 is an apocalyptic number.

20564431 is a deficient number, since it is larger than the sum of its proper divisors (1).

20564431 is an equidigital number, since it uses as much as digits as its factorization.

20564431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20564431 is about 4534.8022007580. The cubic root of 20564431 is about 273.9716124887.

The spelling of 20564431 in words is "twenty million, five hundred sixty-four thousand, four hundred thirty-one".