681261891 has 8 divisors (see below), whose sum is σ = 956157120. Its totient is φ = 430270632.

The previous prime is 681261887. The next prime is 681261899. The reversal of 681261891 is 198162186.

681261891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 681261891 - 2² = 681261887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681261899) 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, 5975925 + ... + 5976038.

It is an arithmetic number, because the mean of its divisors is an integer number (119519640).

Almost surely, 2^681261891 is an apocalyptic number.

681261891 is a deficient number, since it is larger than the sum of its proper divisors (274895229).

681261891 is a wasteful number, since it uses less digits than its factorization.

681261891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11951985.

The product of its digits is 41472, while the sum is 42.

The square root of 681261891 is about 26100.9940615295. The cubic root of 681261891 is about 879.9095512237.

The spelling of 681261891 in words is "six hundred eighty-one million, two hundred sixty-one thousand, eight hundred ninety-one".