23856509 has 2 divisors, whose sum is σ = 23856510. Its totient is φ = 23856508.

The previous prime is 23856487. The next prime is 23856523. The reversal of 23856509 is 90565832.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22534009 + 1322500 = 4747^2 + 1150^2 .

It is a cyclic number.

It is not a de Polignac number, because 23856509 - 2²⁰ = 22807933 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23856409) 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 as a sum of consecutive naturals, namely, 11928254 + 11928255.

It is an arithmetic number, because the mean of its divisors is an integer number (11928255).

Almost surely, 2^23856509 is an apocalyptic number.

It is an amenable number.

23856509 is a deficient number, since it is larger than the sum of its proper divisors (1).

23856509 is an equidigital number, since it uses as much as digits as its factorization.

23856509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 23856509 is about 4884.3125411873. The cubic root of 23856509 is about 287.8739039361.

The spelling of 23856509 in words is "twenty-three million, eight hundred fifty-six thousand, five hundred nine".