666887409 has 12 divisors (see below), whose sum is σ = 963595776. Its totient is φ = 444446712.

The previous prime is 666887399. The next prime is 666887411. The reversal of 666887409 is 904788666.

It is not a de Polignac number, because 666887409 - 2²⁴ = 650110193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666887449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22192 + ... + 42734.

It is an arithmetic number, because the mean of its divisors is an integer number (80299648).

Almost surely, 2^666887409 is an apocalyptic number.

It is an amenable number.

666887409 is a deficient number, since it is larger than the sum of its proper divisors (296708367).

666887409 is a wasteful number, since it uses less digits than its factorization.

666887409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24156 (or 24153 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 54.

The square root of 666887409 is about 25824.1632778295. The cubic root of 666887409 is about 873.6768721915.

The spelling of 666887409 in words is "six hundred sixty-six million, eight hundred eighty-seven thousand, four hundred nine".