57215821 has 8 divisors (see below), whose sum is σ = 64860320. Its totient is φ = 50034672.

The previous prime is 57215803. The next prime is 57215849. The reversal of 57215821 is 12851275.

57215821 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 57215821 - 2¹⁹ = 56691533 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 (57215861) 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, 115575 + ... + 116068.

It is an arithmetic number, because the mean of its divisors is an integer number (8107540).

Almost surely, 2^57215821 is an apocalyptic number.

It is an amenable number.

57215821 is a deficient number, since it is larger than the sum of its proper divisors (7644499).

57215821 is a wasteful number, since it uses less digits than its factorization.

57215821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231675.

The product of its digits is 5600, while the sum is 31.

The square root of 57215821 is about 7564.1140261104. The cubic root of 57215821 is about 385.3352249807.

The spelling of 57215821 in words is "fifty-seven million, two hundred fifteen thousand, eight hundred twenty-one".