557756921 has 4 divisors (see below), whose sum is σ = 557805732. Its totient is φ = 557708112.

The previous prime is 557756917. The next prime is 557756939. The reversal of 557756921 is 129657755.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 14167696 + 543589225 = 3764^2 + 23315^2 .

It is a cyclic number.

It is not a de Polignac number, because 557756921 - 2² = 557756917 is a prime.

It is a super-2 number, since 2×557756921² = 622185565846800482, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (557755921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2975 + ... + 33531.

It is an arithmetic number, because the mean of its divisors is an integer number (139451433).

Almost surely, 2^557756921 is an apocalyptic number.

It is an amenable number.

557756921 is a deficient number, since it is larger than the sum of its proper divisors (48811).

557756921 is a wasteful number, since it uses less digits than its factorization.

557756921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48810.

The product of its digits is 661500, while the sum is 47.

The square root of 557756921 is about 23616.8778842590. The cubic root of 557756921 is about 823.1550672455.

The spelling of 557756921 in words is "five hundred fifty-seven million, seven hundred fifty-six thousand, nine hundred twenty-one".