557821 has 16 divisors (see below), whose sum is σ = 682560. Its totient is φ = 449280.

The previous prime is 557803. The next prime is 557831. The reversal of 557821 is 128755.

557821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 557821 - 2⁵ = 557789 is a prime.

It is a super-2 number, since 2×557821² = 622328536082, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 557821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (557801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3475 + ... + 3631.

It is an arithmetic number, because the mean of its divisors is an integer number (42660).

2⁵⁵⁷⁸²¹ is an apocalyptic number.

It is an amenable number.

557821 is a deficient number, since it is larger than the sum of its proper divisors (124739).

557821 is a wasteful number, since it uses less digits than its factorization.

557821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204.

The product of its digits is 2800, while the sum is 28.

The square root of 557821 is about 746.8741527192. The cubic root of 557821 is about 82.3186589301.

It can be divided in two parts, 557 and 821, that added together give a triangular number (1378 = T₅₂).

The spelling of 557821 in words is "five hundred fifty-seven thousand, eight hundred twenty-one".