20504009 has 2 divisors, whose sum is σ = 20504010. Its totient is φ = 20504008.

The previous prime is 20503999. The next prime is 20504053. The reversal of 20504009 is 90040502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20502784 + 1225 = 4528^2 + 35^2 .

It is a cyclic number.

It is not a de Polignac number, because 20504009 - 2⁴ = 20503993 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20504509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252004 + 10252005.

It is an arithmetic number, because the mean of its divisors is an integer number (10252005).

Almost surely, 2^20504009 is an apocalyptic number.

It is an amenable number.

20504009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20504009 is an equidigital number, since it uses as much as digits as its factorization.

20504009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 20504009 is about 4528.1352674142. The cubic root of 20504009 is about 273.7030232909.

The spelling of 20504009 in words is "twenty million, five hundred four thousand, nine".