681672181 has 4 divisors (see below), whose sum is σ = 681776992. Its totient is φ = 681567372.

The previous prime is 681672151. The next prime is 681672193. The reversal of 681672181 is 181276186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 681672181 - 2⁵ = 681672149 is a prime.

It is a super-2 number, since 2×681672181² = 929353924698593522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681672151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41955 + ... + 55888.

It is an arithmetic number, because the mean of its divisors is an integer number (170444248).

Almost surely, 2^681672181 is an apocalyptic number.

It is an amenable number.

681672181 is a deficient number, since it is larger than the sum of its proper divisors (104811).

681672181 is an equidigital number, since it uses as much as digits as its factorization.

681672181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104810.

The product of its digits is 32256, while the sum is 40.

The square root of 681672181 is about 26108.8525408529. The cubic root of 681672181 is about 880.0861576284.

The spelling of 681672181 in words is "six hundred eighty-one million, six hundred seventy-two thousand, one hundred eighty-one".