391266666 has 96 divisors (see below), whose sum is σ = 1046520000. Its totient is φ = 107914464.

The previous prime is 391266653. The next prime is 391266671. The reversal of 391266666 is 666662193.

It is a nude number because it is divisible by every one of its digits.

391266666 is a modest number, since divided by 66666 gives 3912 as remainder.

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 47 ways as a sum of consecutive naturals, for example, 74185 + ... + 79283.

It is an arithmetic number, because the mean of its divisors is an integer number (10901250).

Almost surely, 2^391266666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391266666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (523260000).

391266666 is an abundant number, since it is smaller than the sum of its proper divisors (655253334).

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

391266666 is a wasteful number, since it uses less digits than its factorization.

391266666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5153 (or 5140 counting only the distinct ones).

The product of its digits is 419904, while the sum is 45.

The square root of 391266666 is about 19780.4617236302. The cubic root of 391266666 is about 731.4044807093.

The spelling of 391266666 in words is "three hundred ninety-one million, two hundred sixty-six thousand, six hundred sixty-six".