57615721 has 4 divisors (see below), whose sum is σ = 59602500. Its totient is φ = 55628944.

The previous prime is 57615689. The next prime is 57615757. The reversal of 57615721 is 12751675.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13579225 + 44036496 = 3685^2 + 6636^2 .

It is a cyclic number.

It is not a de Polignac number, because 57615721 - 2⁵ = 57615689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (57615221) 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, 993346 + ... + 993403.

It is an arithmetic number, because the mean of its divisors is an integer number (14900625).

Almost surely, 2^57615721 is an apocalyptic number.

It is an amenable number.

57615721 is a deficient number, since it is larger than the sum of its proper divisors (1986779).

57615721 is a wasteful number, since it uses less digits than its factorization.

57615721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1986778.

The product of its digits is 14700, while the sum is 34.

The square root of 57615721 is about 7590.5020255580. The cubic root of 57615721 is about 386.2308859671.

The spelling of 57615721 in words is "fifty-seven million, six hundred fifteen thousand, seven hundred twenty-one".