23215531 has 4 divisors (see below), whose sum is σ = 23228632. Its totient is φ = 23202432.

The previous prime is 23215529. The next prime is 23215547. The reversal of 23215531 is 13551232.

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

It is a cyclic number.

It is not a de Polignac number, because 23215531 - 2¹ = 23215529 is a prime.

It is a super-2 number, since 2×23215531² = 1077921759223922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (23215501) 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, 3381 + ... + 7606.

It is an arithmetic number, because the mean of its divisors is an integer number (5807158).

Almost surely, 2^23215531 is an apocalyptic number.

23215531 is a deficient number, since it is larger than the sum of its proper divisors (13101).

23215531 is a wasteful number, since it uses less digits than its factorization.

23215531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13100.

The product of its digits is 900, while the sum is 22.

The square root of 23215531 is about 4818.2497859700. The cubic root of 23215531 is about 285.2722585542.

Adding to 23215531 its reverse (13551232), we get a palindrome (36766763).

The spelling of 23215531 in words is "twenty-three million, two hundred fifteen thousand, five hundred thirty-one".