671644 has 6 divisors (see below), whose sum is σ = 1175384. Its totient is φ = 335820.

The previous prime is 671633. The next prime is 671647. The reversal of 671644 is 446176.

It is a super-2 number, since 2×671644² = 902211325472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83952 + ... + 83959.

2⁶⁷¹⁶⁴⁴ is an apocalyptic number.

It is an amenable number.

671644 is a deficient number, since it is larger than the sum of its proper divisors (503740).

671644 is a wasteful number, since it uses less digits than its factorization.

671644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167915 (or 167913 counting only the distinct ones).

The product of its digits is 4032, while the sum is 28.

The square root of 671644 is about 819.5388947451. The cubic root of 671644 is about 87.5749127163.

It can be divided in two parts, 67 and 1644, that added together give a triangular number (1711 = T₅₈).

The spelling of 671644 in words is "six hundred seventy-one thousand, six hundred forty-four".