647644 has 6 divisors (see below), whose sum is σ = 1133384. Its totient is φ = 323820.

The previous prime is 647641. The next prime is 647651. The reversal of 647644 is 446746.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80952 + ... + 80959.

2⁶⁴⁷⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

647644 is a deficient number, since it is larger than the sum of its proper divisors (485740).

647644 is a wasteful number, since it uses less digits than its factorization.

647644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161915 (or 161913 counting only the distinct ones).

The product of its digits is 16128, while the sum is 31.

The square root of 647644 is about 804.7633192436. The cubic root of 647644 is about 86.5191243758.

The spelling of 647644 in words is "six hundred forty-seven thousand, six hundred forty-four".