666944278 has 32 divisors (see below), whose sum is σ = 1343220480. Its totient is φ = 239859360.

The previous prime is 666944269. The next prime is 666944281. The reversal of 666944278 is 872449666.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 164568 + ... + 168571.

It is an arithmetic number, because the mean of its divisors is an integer number (41975640).

Almost surely, 2^666944278 is an apocalyptic number.

666944278 is an abundant number, since it is smaller than the sum of its proper divisors (676276202).

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

666944278 is a wasteful number, since it uses less digits than its factorization.

666944278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333172.

The product of its digits is 3483648, while the sum is 52.

The square root of 666944278 is about 25825.2643355300. The cubic root of 666944278 is about 873.7017058277.

The spelling of 666944278 in words is "six hundred sixty-six million, nine hundred forty-four thousand, two hundred seventy-eight".