57039721 has 4 divisors (see below), whose sum is σ = 58879744. Its totient is φ = 55199700.

The previous prime is 57039707. The next prime is 57039751. The reversal of 57039721 is 12793075.

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 a de Polignac number, because none of the positive numbers 2^k-57039721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (57039751) 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, 919965 + ... + 920026.

It is an arithmetic number, because the mean of its divisors is an integer number (14719936).

Almost surely, 2^57039721 is an apocalyptic number.

It is an amenable number.

57039721 is a deficient number, since it is larger than the sum of its proper divisors (1840023).

57039721 is a wasteful number, since it uses less digits than its factorization.

57039721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1840022.

The product of its (nonzero) digits is 13230, while the sum is 34.

The square root of 57039721 is about 7552.4645646305. The cubic root of 57039721 is about 384.9394878753.

The spelling of 57039721 in words is "fifty-seven million, thirty-nine thousand, seven hundred twenty-one".