647645 has 4 divisors (see below), whose sum is σ = 777180. Its totient is φ = 518112.

The previous prime is 647641. The next prime is 647651. The reversal of 647645 is 546746.

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

It can be written as a sum of positive squares in 2 ways, for example, as 395641 + 252004 = 629^2 + 502^2 .

It is a cyclic number.

It is not a de Polignac number, because 647645 - 2² = 647641 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 647645.

It is not an unprimeable number, because it can be changed into a prime (647641) 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, 64760 + ... + 64769.

It is an arithmetic number, because the mean of its divisors is an integer number (194295).

2⁶⁴⁷⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

647645 is a deficient number, since it is larger than the sum of its proper divisors (129535).

647645 is a wasteful number, since it uses less digits than its factorization.

647645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129534.

The product of its digits is 20160, while the sum is 32.

The square root of 647645 is about 804.7639405441. The cubic root of 647645 is about 86.5191689060.

The spelling of 647645 in words is "six hundred forty-seven thousand, six hundred forty-five".