23190721 has 4 divisors (see below), whose sum is σ = 23207472. Its totient is φ = 23173972.

The previous prime is 23190719. The next prime is 23190743. The reversal of 23190721 is 12709132.

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 23190721 - 2¹ = 23190719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23199721) 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, 6091 + ... + 9136.

It is an arithmetic number, because the mean of its divisors is an integer number (5801868).

Almost surely, 2^23190721 is an apocalyptic number.

23190721 is the 3046-th heptagonal number.

It is an amenable number.

23190721 is a deficient number, since it is larger than the sum of its proper divisors (16751).

23190721 is a wasteful number, since it uses less digits than its factorization.

23190721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16750.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 23190721 is about 4815.6745114262. The cubic root of 23190721 is about 285.1706006386.

Adding to 23190721 its reverse (12709132), we get a palindrome (35899853).

The spelling of 23190721 in words is "twenty-three million, one hundred ninety thousand, seven hundred twenty-one".