23813509 has 4 divisors (see below), whose sum is σ = 23831820. Its totient is φ = 23795200.

The previous prime is 23813453. The next prime is 23813519. The reversal of 23813509 is 90531832.

It is a happy number.

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 13068225 + 10745284 = 3615^2 + 3278^2 .

It is a cyclic number.

It is not a de Polignac number, because 23813509 - 2⁷ = 23813381 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23813519) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7042 + ... + 9859.

It is an arithmetic number, because the mean of its divisors is an integer number (5957955).

Almost surely, 2^23813509 is an apocalyptic number.

It is an amenable number.

23813509 is a deficient number, since it is larger than the sum of its proper divisors (18311).

23813509 is a wasteful number, since it uses less digits than its factorization.

23813509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18310.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 23813509 is about 4879.9087081625. The cubic root of 23813509 is about 287.7008411386.

The spelling of 23813509 in words is "twenty-three million, eight hundred thirteen thousand, five hundred nine".