23081721 has 16 divisors (see below), whose sum is σ = 33265344. Its totient is φ = 14151744.

The previous prime is 23081717. The next prime is 23081741. The reversal of 23081721 is 12718032.

It is not a de Polignac number, because 23081721 - 2² = 23081717 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 23081691 and 23081700.

It is not an unprimeable number, because it can be changed into a prime (23081711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11430 + ... + 13296.

It is an arithmetic number, because the mean of its divisors is an integer number (2079084).

Almost surely, 2^23081721 is an apocalyptic number.

It is an amenable number.

23081721 is a deficient number, since it is larger than the sum of its proper divisors (10183623).

23081721 is a wasteful number, since it uses less digits than its factorization.

23081721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 23081721 is about 4804.3439718655. The cubic root of 23081721 is about 284.7231167466.

Adding to 23081721 its reverse (12718032), we get a palindrome (35799753).

The spelling of 23081721 in words is "twenty-three million, eighty-one thousand, seven hundred twenty-one".