666577866 has 32 divisors (see below), whose sum is σ = 1391660928. Its totient is φ = 212639040.

The previous prime is 666577861. The next prime is 666577867. The reversal of 666577866 is 668775666.

It is a happy number.

It is a super-2 number, since 2×666577866² = 888652102882227912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666577861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11070 + ... + 38153.

It is an arithmetic number, because the mean of its divisors is an integer number (43489404).

Almost surely, 2^666577866 is an apocalyptic number.

666577866 is an abundant number, since it is smaller than the sum of its proper divisors (725083062).

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

666577866 is a wasteful number, since it uses less digits than its factorization.

666577866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49326.

The product of its digits is 15240960, while the sum is 57.

The square root of 666577866 is about 25818.1692999329. The cubic root of 666577866 is about 873.5416757502.

The spelling of 666577866 in words is "six hundred sixty-six million, five hundred seventy-seven thousand, eight hundred sixty-six".