671655681 has 24 divisors (see below), whose sum is σ = 1027538720. Its totient is φ = 421583616.

The previous prime is 671655679. The next prime is 671655713. The reversal of 671655681 is 186556176.

671655681 is a `hidden beast` number, since 6 + 7 + 16 + 556 + 81 = 666.

It is not a de Polignac number, because 671655681 - 2¹ = 671655679 is a prime.

It is a super-2 number, since 2×671655681² = 902242707639147522, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (671655181) 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, 15825 + ... + 39921.

Almost surely, 2^671655681 is an apocalyptic number.

It is an amenable number.

671655681 is a deficient number, since it is larger than the sum of its proper divisors (355883039).

671655681 is a wasteful number, since it uses less digits than its factorization.

671655681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24285 (or 24282 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The square root of 671655681 is about 25916.3207458158. The cubic root of 671655681 is about 875.7542040419.

The spelling of 671655681 in words is "six hundred seventy-one million, six hundred fifty-five thousand, six hundred eighty-one".