56724221 has 4 divisors (see below), whose sum is σ = 56740092. Its totient is φ = 56708352.

The previous prime is 56724209. The next prime is 56724251. The reversal of 56724221 is 12242765.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12242765 = 5 ⋅2448553.

It can be written as a sum of positive squares in 2 ways, for example, as 34351321 + 22372900 = 5861^2 + 4730^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56724221 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 (56724251) 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, 221 + ... + 10653.

It is an arithmetic number, because the mean of its divisors is an integer number (14185023).

Almost surely, 2^56724221 is an apocalyptic number.

It is an amenable number.

56724221 is a deficient number, since it is larger than the sum of its proper divisors (15871).

56724221 is a wasteful number, since it uses less digits than its factorization.

56724221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15870.

The product of its digits is 6720, while the sum is 29.

The square root of 56724221 is about 7531.5483799814. The cubic root of 56724221 is about 384.2284452501.

Adding to 56724221 its reverse (12242765), we get a palindrome (68966986).

The spelling of 56724221 in words is "fifty-six million, seven hundred twenty-four thousand, two hundred twenty-one".