56531221 has 4 divisors (see below), whose sum is σ = 56561344. Its totient is φ = 56501100.

The previous prime is 56531219. The next prime is 56531249. The reversal of 56531221 is 12213565.

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.

It is a cyclic number.

It is not a de Polignac number, because 56531221 - 2¹ = 56531219 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 (56531281) 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, 12045 + ... + 16066.

It is an arithmetic number, because the mean of its divisors is an integer number (14140336).

Almost surely, 2^56531221 is an apocalyptic number.

It is an amenable number.

56531221 is a deficient number, since it is larger than the sum of its proper divisors (30123).

56531221 is a wasteful number, since it uses less digits than its factorization.

56531221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30122.

The product of its digits is 1800, while the sum is 25.

The square root of 56531221 is about 7518.7246923930. The cubic root of 56531221 is about 383.7921803911.

Adding to 56531221 its reverse (12213565), we get a palindrome (68744786).

The spelling of 56531221 in words is "fifty-six million, five hundred thirty-one thousand, two hundred twenty-one".