665712139 has 8 divisors (see below), whose sum is σ = 724914000. Its totient is φ = 608926752.

The previous prime is 665712137. The next prime is 665712143. The reversal of 665712139 is 931217566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 665712139 - 2¹ = 665712137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665712133) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 603544 + ... + 604645.

It is an arithmetic number, because the mean of its divisors is an integer number (90614250).

Almost surely, 2^665712139 is an apocalyptic number.

665712139 is a deficient number, since it is larger than the sum of its proper divisors (59201861).

665712139 is a wasteful number, since it uses less digits than its factorization.

665712139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1208237.

The product of its digits is 68040, while the sum is 40.

The square root of 665712139 is about 25801.3980047594. The cubic root of 665712139 is about 873.1633372317.

The spelling of 665712139 in words is "six hundred sixty-five million, seven hundred twelve thousand, one hundred thirty-nine".