666977408 has 64 divisors (see below), whose sum is σ = 1365984000. Its totient is φ = 324280320.

The previous prime is 666977407. The next prime is 666977417. The reversal of 666977408 is 804779666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 666977408.

It is not an unprimeable number, because it can be changed into a prime (666977401) 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, 717488 + ... + 718416.

It is an arithmetic number, because the mean of its divisors is an integer number (21343500).

Almost surely, 2^666977408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666977408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (682992000).

666977408 is an abundant number, since it is smaller than the sum of its proper divisors (699006592).

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

666977408 is an equidigital number, since it uses as much as digits as its factorization.

666977408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1093 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 53.

The square root of 666977408 is about 25825.9057537195. The cubic root of 666977408 is about 873.7161724327.

The spelling of 666977408 in words is "six hundred sixty-six million, nine hundred seventy-seven thousand, four hundred eight".