56721161 has 4 divisors (see below), whose sum is σ = 64824192. Its totient is φ = 48618132.

The previous prime is 56721157. The next prime is 56721179. The reversal of 56721161 is 16112765.

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 56721161 - 2² = 56721157 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (56751161) 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, 4051505 + ... + 4051518.

It is an arithmetic number, because the mean of its divisors is an integer number (16206048).

Almost surely, 2^56721161 is an apocalyptic number.

It is an amenable number.

56721161 is a deficient number, since it is larger than the sum of its proper divisors (8103031).

56721161 is an equidigital number, since it uses as much as digits as its factorization.

56721161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8103030.

The product of its digits is 2520, while the sum is 29.

The square root of 56721161 is about 7531.3452317630. The cubic root of 56721161 is about 384.2215360311.

The spelling of 56721161 in words is "fifty-six million, seven hundred twenty-one thousand, one hundred sixty-one".