23028721 has 4 divisors (see below), whose sum is σ = 23073444. Its totient is φ = 22984000.

The previous prime is 23028713. The next prime is 23028739. The reversal of 23028721 is 12782032.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5085025 + 17943696 = 2255^2 + 4236^2 .

It is a cyclic number.

It is not a de Polignac number, because 23028721 - 2³ = 23028713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23028121) 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, 21580 + ... + 22621.

It is an arithmetic number, because the mean of its divisors is an integer number (5768361).

Almost surely, 2^23028721 is an apocalyptic number.

It is an amenable number.

23028721 is a deficient number, since it is larger than the sum of its proper divisors (44723).

23028721 is an equidigital number, since it uses as much as digits as its factorization.

23028721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44722.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 23028721 is about 4798.8249603419. The cubic root of 23028721 is about 284.5050236788.

The spelling of 23028721 in words is "twenty-three million, twenty-eight thousand, seven hundred twenty-one".