681820865 has 16 divisors (see below), whose sum is σ = 893077056. Its totient is φ = 495585600.

The previous prime is 681820861. The next prime is 681820879. The reversal of 681820865 is 568028186.

It is not a de Polignac number, because 681820865 - 2² = 681820861 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (681820861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 167555 + ... + 171575.

It is an arithmetic number, because the mean of its divisors is an integer number (55817316).

Almost surely, 2^681820865 is an apocalyptic number.

It is an amenable number.

681820865 is a deficient number, since it is larger than the sum of its proper divisors (211256191).

681820865 is a wasteful number, since it uses less digits than its factorization.

681820865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7120.

The product of its (nonzero) digits is 184320, while the sum is 44.

The square root of 681820865 is about 26111.6997723243. The cubic root of 681820865 is about 880.1501401023.

The spelling of 681820865 in words is "six hundred eighty-one million, eight hundred twenty thousand, eight hundred sixty-five".