23921809 has 4 divisors (see below), whose sum is σ = 23999040. Its totient is φ = 23844580.

The previous prime is 23921789. The next prime is 23921813. The reversal of 23921809 is 90812932.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 23921809 - 2²¹ = 21824657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23921899) 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, 38149 + ... + 38770.

It is an arithmetic number, because the mean of its divisors is an integer number (5999760).

Almost surely, 2^23921809 is an apocalyptic number.

It is an amenable number.

23921809 is a deficient number, since it is larger than the sum of its proper divisors (77231).

23921809 is an equidigital number, since it uses as much as digits as its factorization.

23921809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77230.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 23921809 is about 4890.9926395365. The cubic root of 23921809 is about 288.1363206560.

The spelling of 23921809 in words is "twenty-three million, nine hundred twenty-one thousand, eight hundred nine".