23206721 has 4 divisors (see below), whose sum is σ = 23218944. Its totient is φ = 23194500.

The previous prime is 23206643. The next prime is 23206727. The reversal of 23206721 is 12760232.

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 a de Polignac number, because none of the positive numbers 2^k-23206721 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (23206727) 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, 2585 + ... + 7286.

It is an arithmetic number, because the mean of its divisors is an integer number (5804736).

Almost surely, 2^23206721 is an apocalyptic number.

It is an amenable number.

23206721 is a deficient number, since it is larger than the sum of its proper divisors (12223).

23206721 is an equidigital number, since it uses as much as digits as its factorization.

23206721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12222.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 23206721 is about 4817.3354668323. The cubic root of 23206721 is about 285.2361682521.

Adding to 23206721 its reverse (12760232), we get a palindrome (35966953).

The spelling of 23206721 in words is "twenty-three million, two hundred six thousand, seven hundred twenty-one".