666661158 has 16 divisors (see below), whose sum is σ = 1481469360. Its totient is φ = 222220368.

The previous prime is 666661147. The next prime is 666661159. The reversal of 666661158 is 851166666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666661159) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6172735 + ... + 6172842.

It is an arithmetic number, because the mean of its divisors is an integer number (92591835).

Almost surely, 2^666661158 is an apocalyptic number.

666661158 is an abundant number, since it is smaller than the sum of its proper divisors (814808202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666661158 is a wasteful number, since it uses less digits than its factorization.

666661158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12345588 (or 12345582 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 666661158 is about 25819.7822996244. The cubic root of 666661158 is about 873.5780585979.

The spelling of 666661158 in words is "six hundred sixty-six million, six hundred sixty-one thousand, one hundred fifty-eight".