666542408 has 64 divisors (see below), whose sum is σ = 1482624000. Its totient is φ = 274901760.

The previous prime is 666542399. The next prime is 666542413. The reversal of 666542408 is 804245666.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 341018 + ... + 342966.

It is an arithmetic number, because the mean of its divisors is an integer number (23166000).

Almost surely, 2^666542408 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 666542408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (741312000).

666542408 is an abundant number, since it is smaller than the sum of its proper divisors (816081592).

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

666542408 is a wasteful number, since it uses less digits than its factorization.

666542408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190 (or 2186 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 41.

The square root of 666542408 is about 25817.4826038481. The cubic root of 666542408 is about 873.5261863920.

The spelling of 666542408 in words is "six hundred sixty-six million, five hundred forty-two thousand, four hundred eight".