666122257 has 12 divisors (see below), whose sum is σ = 700687260. Its totient is φ = 632506560.

The previous prime is 666122221. The next prime is 666122263. The reversal of 666122257 is 752221666.

It can be written as a sum of positive squares in 6 ways, for example, as 434138896 + 231983361 = 20836^2 + 15231^2 .

It is not a de Polignac number, because 666122257 - 2⁷ = 666122129 is a prime.

It is a super-2 number, since 2×666122257² = 887437722541548098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666128257) 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 11 ways as a sum of consecutive naturals, for example, 104823 + ... + 110995.

It is an arithmetic number, because the mean of its divisors is an integer number (58390605).

Almost surely, 2^666122257 is an apocalyptic number.

It is an amenable number.

666122257 is a deficient number, since it is larger than the sum of its proper divisors (34565003).

666122257 is an equidigital number, since it uses as much as digits as its factorization.

666122257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6324 (or 6263 counting only the distinct ones).

The product of its digits is 60480, while the sum is 37.

The square root of 666122257 is about 25809.3443736954. The cubic root of 666122257 is about 873.3426071538.

The spelling of 666122257 in words is "six hundred sixty-six million, one hundred twenty-two thousand, two hundred fifty-seven".