644692 has 12 divisors (see below), whose sum is σ = 1149876. Its totient is φ = 316160.

The previous prime is 644687. The next prime is 644701. The reversal of 644692 is 296446.

644692 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 568516 + 76176 = 754^2 + 276^2 .

It is a congruent number.

It is an unprimeable number.

644692 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1309 + ... + 1732.

It is an arithmetic number, because the mean of its divisors is an integer number (95823).

2⁶⁴⁴⁶⁹² is an apocalyptic number.

It is an amenable number.

644692 is a deficient number, since it is larger than the sum of its proper divisors (505184).

644692 is a wasteful number, since it uses less digits than its factorization.

644692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3098 (or 3096 counting only the distinct ones).

The product of its digits is 10368, while the sum is 31.

The square root of 644692 is about 802.9271448892. The cubic root of 644692 is about 86.3874710342.

The spelling of 644692 in words is "six hundred forty-four thousand, six hundred ninety-two".