671780861 has 8 divisors (see below), whose sum is σ = 683956224. Its totient is φ = 659643120.

The previous prime is 671780801. The next prime is 671780869. The reversal of 671780861 is 168087176.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671780861 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 (671780869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27956 + ... + 46098.

It is an arithmetic number, because the mean of its divisors is an integer number (85494528).

Almost surely, 2^671780861 is an apocalyptic number.

671780861 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

671780861 is a deficient number, since it is larger than the sum of its proper divisors (12175363).

671780861 is a wasteful number, since it uses less digits than its factorization.

671780861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18811.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 671780861 is about 25918.7357137651. The cubic root of 671780861 is about 875.8086069671.

It can be divided in two parts, 6717 and 80861, that added together give a palindrome (87578).

The spelling of 671780861 in words is "six hundred seventy-one million, seven hundred eighty thousand, eight hundred sixty-one".