644702 has 4 divisors (see below), whose sum is σ = 967056. Its totient is φ = 322350.

The previous prime is 644701. The next prime is 644717. The reversal of 644702 is 207446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 207446 = 2 ⋅103723.

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 644702.

It is not an unprimeable number, because it can be changed into a prime (644701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161174 + ... + 161177.

It is an arithmetic number, because the mean of its divisors is an integer number (241764).

2⁶⁴⁴⁷⁰² is an apocalyptic number.

644702 is a deficient number, since it is larger than the sum of its proper divisors (322354).

644702 is a wasteful number, since it uses less digits than its factorization.

644702 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322353.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 644702 is about 802.9333720801. The cubic root of 644702 is about 86.3879176920.

The spelling of 644702 in words is "six hundred forty-four thousand, seven hundred two".