23457821 has 4 divisors (see below), whose sum is σ = 23469600. Its totient is φ = 23446044.

The previous prime is 23457817. The next prime is 23457823. The reversal of 23457821 is 12875432.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 23457821 - 2² = 23457817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23457823) 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 in 3 ways as a sum of consecutive naturals, for example, 2081 + ... + 7158.

It is an arithmetic number, because the mean of its divisors is an integer number (5867400).

Almost surely, 2^23457821 is an apocalyptic number.

It is an amenable number.

23457821 is a deficient number, since it is larger than the sum of its proper divisors (11779).

23457821 is an equidigital number, since it uses as much as digits as its factorization.

23457821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11778.

The product of its digits is 13440, while the sum is 32.

The square root of 23457821 is about 4843.3274718937. The cubic root of 23457821 is about 286.2612451485.

The spelling of 23457821 in words is "twenty-three million, four hundred fifty-seven thousand, eight hundred twenty-one".