671000661 has 24 divisors (see below), whose sum is σ = 997139000. Its totient is φ = 434491776.

The previous prime is 671000657. The next prime is 671000683. The reversal of 671000661 is 166000176.

It can be written as a sum of positive squares in 4 ways, for example, as 293436900 + 377563761 = 17130^2 + 19431^2 .

It is not a de Polignac number, because 671000661 - 2² = 671000657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671000651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 242715 + ... + 245463.

Almost surely, 2^671000661 is an apocalyptic number.

It is an amenable number.

671000661 is a deficient number, since it is larger than the sum of its proper divisors (326138339).

671000661 is a wasteful number, since it uses less digits than its factorization.

671000661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3525 (or 3522 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 671000661 is about 25903.6804527851. The cubic root of 671000661 is about 875.4694236540.

The spelling of 671000661 in words is "six hundred seventy-one million, six hundred sixty-one", and thus it is an aban number.