56721181 has 4 divisors (see below), whose sum is σ = 61877664. Its totient is φ = 51564700.

The previous prime is 56721179. The next prime is 56721199. The reversal of 56721181 is 18112765.

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 not a de Polignac number, because 56721181 - 2¹ = 56721179 is a prime.

It is a super-2 number, since 2×56721181² = 6434584748069522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56721781) 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, 2578225 + ... + 2578246.

It is an arithmetic number, because the mean of its divisors is an integer number (15469416).

Almost surely, 2^56721181 is an apocalyptic number.

It is an amenable number.

56721181 is a deficient number, since it is larger than the sum of its proper divisors (5156483).

56721181 is a wasteful number, since it uses less digits than its factorization.

56721181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5156482.

The product of its digits is 3360, while the sum is 31.

The square root of 56721181 is about 7531.3465595470. The cubic root of 56721181 is about 384.2215811902.

The spelling of 56721181 in words is "fifty-six million, seven hundred twenty-one thousand, one hundred eighty-one".