139623666 has 128 divisors (see below), whose sum is σ = 371374080. Its totient is φ = 33965568.

The previous prime is 139623613. The next prime is 139623683. The reversal of 139623666 is 666326931.

139623666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 445926 + ... + 446238.

It is an arithmetic number, because the mean of its divisors is an integer number (2901360).

Almost surely, 2^139623666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 139623666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185687040).

139623666 is an abundant number, since it is smaller than the sum of its proper divisors (231750414).

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

139623666 is a wasteful number, since it uses less digits than its factorization.

139623666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400.

The product of its digits is 209952, while the sum is 42.

The square root of 139623666 is about 11816.2458505229. The cubic root of 139623666 is about 518.7837278888.

The spelling of 139623666 in words is "one hundred thirty-nine million, six hundred twenty-three thousand, six hundred sixty-six".