23216021 has 4 divisors (see below), whose sum is σ = 23225952. Its totient is φ = 23206092.

The previous prime is 23216003. The next prime is 23216023. The reversal of 23216021 is 12061232.

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 not a de Polignac number, because 23216021 - 2⁶ = 23215957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23216023) 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, 686 + ... + 6848.

It is an arithmetic number, because the mean of its divisors is an integer number (5806488).

Almost surely, 2^23216021 is an apocalyptic number.

It is an amenable number.

23216021 is a deficient number, since it is larger than the sum of its proper divisors (9931).

23216021 is an equidigital number, since it uses as much as digits as its factorization.

23216021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9930.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 23216021 is about 4818.3006340410. The cubic root of 23216021 is about 285.2742655787.

Adding to 23216021 its reverse (12061232), we get a palindrome (35277253).

The spelling of 23216021 in words is "twenty-three million, two hundred sixteen thousand, twenty-one".