671668 has 6 divisors (see below), whose sum is σ = 1175426. Its totient is φ = 335832.

The previous prime is 671651. The next prime is 671681. The reversal of 671668 is 866176.

It can be written as a sum of positive squares in only one way, i.e., 550564 + 121104 = 742^2 + 348^2 .

It is a super-2 number, since 2×671668² = 902275804448, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

671668 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 as a sum of consecutive naturals, namely, 83955 + ... + 83962.

2⁶⁷¹⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

671668 is a deficient number, since it is larger than the sum of its proper divisors (503758).

671668 is a wasteful number, since it uses less digits than its factorization.

671668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167921 (or 167919 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 671668 is about 819.5535369944. The cubic root of 671668 is about 87.5759558149.

The spelling of 671668 in words is "six hundred seventy-one thousand, six hundred sixty-eight".