671877981 has 24 divisors (see below), whose sum is σ = 1023409920. Its totient is φ = 423579456.

The previous prime is 671877959. The next prime is 671877991. The reversal of 671877981 is 189778176.

It is not a de Polignac number, because 671877981 - 2⁵ = 671877949 is a prime.

It is a super-2 number, since 2×671877981² = 902840042705272722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671877901) 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, 100561 + ... + 107033.

It is an arithmetic number, because the mean of its divisors is an integer number (42642080).

Almost surely, 2^671877981 is an apocalyptic number.

It is an amenable number.

671877981 is a deficient number, since it is larger than the sum of its proper divisors (351531939).

671877981 is a wasteful number, since it uses less digits than its factorization.

671877981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7105 (or 7102 counting only the distinct ones).

The product of its digits is 1185408, while the sum is 54.

The square root of 671877981 is about 25920.6091942300. The cubic root of 671877981 is about 875.8508104287.

The spelling of 671877981 in words is "six hundred seventy-one million, eight hundred seventy-seven thousand, nine hundred eighty-one".