557991 has 24 divisors (see below), whose sum is σ = 977184. Its totient is φ = 299520.

The previous prime is 557987. The next prime is 558007. The reversal of 557991 is 199755.

It is a happy number.

It is not a de Polignac number, because 557991 - 2² = 557987 is a prime.

It is a super-2 number, since 2×557991² = 622707912162, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (557981) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 811 + ... + 1331.

It is an arithmetic number, because the mean of its divisors is an integer number (40716).

2⁵⁵⁷⁹⁹¹ is an apocalyptic number.

557991 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

557991 is a deficient number, since it is larger than the sum of its proper divisors (419193).

557991 is a wasteful number, since it uses less digits than its factorization.

557991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 551 (or 548 counting only the distinct ones).

The product of its digits is 14175, while the sum is 36.

The square root of 557991 is about 746.9879517101. The cubic root of 557991 is about 82.3270204837.

The spelling of 557991 in words is "five hundred fifty-seven thousand, nine hundred ninety-one".