23219721 has 24 divisors (see below), whose sum is σ = 38910144. Its totient is φ = 13068000.

The previous prime is 23219689. The next prime is 23219731. The reversal of 23219721 is 12791232.

It is not a de Polignac number, because 23219721 - 2⁵ = 23219689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (23219731) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1471 + ... + 6971.

It is an arithmetic number, because the mean of its divisors is an integer number (1621256).

Almost surely, 2^23219721 is an apocalyptic number.

23219721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

23219721 is a deficient number, since it is larger than the sum of its proper divisors (15690423).

23219721 is a wasteful number, since it uses less digits than its factorization.

23219721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5581 (or 5578 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 23219721 is about 4818.6845715402. The cubic root of 23219721 is about 285.2894197505.

The spelling of 23219721 in words is "twenty-three million, two hundred nineteen thousand, seven hundred twenty-one".