57221661 has 16 divisors (see below), whose sum is σ = 88976000. Its totient is φ = 32697504.

The previous prime is 57221657. The next prime is 57221663. The reversal of 57221661 is 16612275.

It is not a de Polignac number, because 57221661 - 2² = 57221657 is a prime.

It is the 7565-th Hogben number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (57221663) by changing a digit.

It is a nontrivial repunit in base 7564.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26776 + ... + 28833.

It is an arithmetic number, because the mean of its divisors is an integer number (5561000).

Almost surely, 2^57221661 is an apocalyptic number.

It is an amenable number.

57221661 is a deficient number, since it is larger than the sum of its proper divisors (31754339).

57221661 is an equidigital number, since it uses as much as digits as its factorization.

57221661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55633 (or 55619 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 57221661 is about 7564.5000495737. The cubic root of 57221661 is about 385.3483348812.

The spelling of 57221661 in words is "fifty-seven million, two hundred twenty-one thousand, six hundred sixty-one".