57721021 has 8 divisors (see below), whose sum is σ = 58171680. Its totient is φ = 57272688.

The previous prime is 57721019. The next prime is 57721051. The reversal of 57721021 is 12012775.

It is a happy number.

57721021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 57721021 - 2¹ = 57721019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (57721051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137550 + ... + 137968.

It is an arithmetic number, because the mean of its divisors is an integer number (7271460).

Almost surely, 2^57721021 is an apocalyptic number.

It is an amenable number.

57721021 is a deficient number, since it is larger than the sum of its proper divisors (450659).

57721021 is a wasteful number, since it uses less digits than its factorization.

57721021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1163.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 57721021 is about 7597.4351593153. The cubic root of 57721021 is about 386.4660379946.

Adding to 57721021 its reverse (12012775), we get a palindrome (69733796).

The spelling of 57721021 in words is "fifty-seven million, seven hundred twenty-one thousand, twenty-one".