666139392 has 108 divisors (see below), whose sum is σ = 2021863480. Its totient is φ = 210345984.

The previous prime is 666139391. The next prime is 666139399. The reversal of 666139392 is 293931666.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (666139391) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36168 + ... + 51384.

Almost surely, 2^666139392 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 666139392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1010931740).

666139392 is an abundant number, since it is smaller than the sum of its proper divisors (1355724088).

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

666139392 is a wasteful number, since it uses less digits than its factorization.

666139392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15258 (or 15241 counting only the distinct ones).

The product of its digits is 314928, while the sum is 45.

The square root of 666139392 is about 25809.6763249755. The cubic root of 666139392 is about 873.3500955675.

The spelling of 666139392 in words is "six hundred sixty-six million, one hundred thirty-nine thousand, three hundred ninety-two".