666879894 has 48 divisors (see below), whose sum is σ = 1516320000. Its totient is φ = 211417008.

The previous prime is 666879833. The next prime is 666879901. The reversal of 666879894 is 498978666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69607 + ... + 78605.

It is an arithmetic number, because the mean of its divisors is an integer number (31590000).

Almost surely, 2^666879894 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666879894, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (758160000).

666879894 is an abundant number, since it is smaller than the sum of its proper divisors (849440106).

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

666879894 is a wasteful number, since it uses less digits than its factorization.

666879894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9209 (or 9206 counting only the distinct ones).

The product of its digits is 31352832, while the sum is 63.

The square root of 666879894 is about 25824.0177741575. The cubic root of 666879894 is about 873.6735904250.

The spelling of 666879894 in words is "six hundred sixty-six million, eight hundred seventy-nine thousand, eight hundred ninety-four".