644474 has 4 divisors (see below), whose sum is σ = 966714. Its totient is φ = 322236.

The previous prime is 644447. The next prime is 644489. The reversal of 644474 is 474446.

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

It can be written as a sum of positive squares in only one way, i.e., 628849 + 15625 = 793^2 + 125^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161117 + ... + 161120.

2⁶⁴⁴⁴⁷⁴ is an apocalyptic number.

644474 is a deficient number, since it is larger than the sum of its proper divisors (322240).

644474 is a wasteful number, since it uses less digits than its factorization.

644474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322239.

The product of its digits is 10752, while the sum is 29.

The square root of 644474 is about 802.7913801231. The cubic root of 644474 is about 86.3777327448.

The spelling of 644474 in words is "six hundred forty-four thousand, four hundred seventy-four".