660505647 has 4 divisors (see below), whose sum is σ = 880674200. Its totient is φ = 440337096.

The previous prime is 660505627. The next prime is 660505691. The reversal of 660505647 is 746505066.

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

It is a de Polignac number, because none of the positive numbers 2^k-660505647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660505627) 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, 110084272 + ... + 110084277.

It is an arithmetic number, because the mean of its divisors is an integer number (220168550).

Almost surely, 2^660505647 is an apocalyptic number.

660505647 is a deficient number, since it is larger than the sum of its proper divisors (220168553).

660505647 is a wasteful number, since it uses less digits than its factorization.

660505647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220168552.

The product of its (nonzero) digits is 151200, while the sum is 39.

The square root of 660505647 is about 25700.3044145395. The cubic root of 660505647 is about 870.8810588212.

The spelling of 660505647 in words is "six hundred sixty million, five hundred five thousand, six hundred forty-seven".