660726739 has 4 divisors (see below), whose sum is σ = 661872424. Its totient is φ = 659581056.

The previous prime is 660726719. The next prime is 660726757. The reversal of 660726739 is 937627066.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 660726739 - 2²⁵ = 627172307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660726719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 571977 + ... + 573130.

It is an arithmetic number, because the mean of its divisors is an integer number (165468106).

Almost surely, 2^660726739 is an apocalyptic number.

660726739 is a deficient number, since it is larger than the sum of its proper divisors (1145685).

660726739 is a wasteful number, since it uses less digits than its factorization.

660726739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145684.

The product of its (nonzero) digits is 571536, while the sum is 46.

The square root of 660726739 is about 25704.6054044796. The cubic root of 660726739 is about 870.9782184021.

The spelling of 660726739 in words is "six hundred sixty million, seven hundred twenty-six thousand, seven hundred thirty-nine".