557208721 has 2 divisors, whose sum is σ = 557208722. Its totient is φ = 557208720.

The previous prime is 557208719. The next prime is 557208727. The reversal of 557208721 is 127802755.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 551733121 + 5475600 = 23489^2 + 2340^2 .

It is a cyclic number.

It is not a de Polignac number, because 557208721 - 2¹ = 557208719 is a prime.

Together with 557208719, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (557208727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 278604360 + 278604361.

It is an arithmetic number, because the mean of its divisors is an integer number (278604361).

Almost surely, 2^557208721 is an apocalyptic number.

It is an amenable number.

557208721 is a deficient number, since it is larger than the sum of its proper divisors (1).

557208721 is an equidigital number, since it uses as much as digits as its factorization.

557208721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39200, while the sum is 37.

The square root of 557208721 is about 23605.2689245431. The cubic root of 557208721 is about 822.8852952880.

The spelling of 557208721 in words is "five hundred fifty-seven million, two hundred eight thousand, seven hundred twenty-one".