666977440 has 48 divisors (see below), whose sum is σ = 1605485448. Its totient is φ = 261753856.

The previous prime is 666977417. The next prime is 666977489. The reversal of 666977440 is 44779666.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 661724176 + 5253264 = 25724^2 + 2292^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30847 + ... + 47806.

Almost surely, 2^666977440 is an apocalyptic number.

It is an amenable number.

666977440 is an abundant number, since it is smaller than the sum of its proper divisors (938508008).

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

666977440 is a wasteful number, since it uses less digits than its factorization.

666977440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78721 (or 78713 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 49.

The square root of 666977440 is about 25825.9063732524. The cubic root of 666977440 is about 873.7161864056.

The spelling of 666977440 in words is "six hundred sixty-six million, nine hundred seventy-seven thousand, four hundred forty".