668272139 has 4 divisors (see below), whose sum is σ = 676731360. Its totient is φ = 659812920.

The previous prime is 668272117. The next prime is 668272147. The reversal of 668272139 is 931272866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 931272866 = 2 ⋅465636433.

It is a cyclic number.

It is not a de Polignac number, because 668272139 - 2²⁰ = 667223563 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 668272139.

It is not an unprimeable number, because it can be changed into a prime (668272109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4229492 + ... + 4229649.

It is an arithmetic number, because the mean of its divisors is an integer number (169182840).

Almost surely, 2^668272139 is an apocalyptic number.

668272139 is a deficient number, since it is larger than the sum of its proper divisors (8459221).

668272139 is an equidigital number, since it uses as much as digits as its factorization.

668272139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8459220.

The product of its digits is 217728, while the sum is 44.

The square root of 668272139 is about 25850.9601175662. The cubic root of 668272139 is about 874.2811571993.

The spelling of 668272139 in words is "six hundred sixty-eight million, two hundred seventy-two thousand, one hundred thirty-nine".