681866861 has 8 divisors (see below), whose sum is σ = 734536320. Its totient is φ = 629228592.

The previous prime is 681866837. The next prime is 681866873. The reversal of 681866861 is 168668186.

It is a happy number.

681866861 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 a cyclic number.

It is not a de Polignac number, because 681866861 - 2¹⁰ = 681865837 is a prime.

It is a super-2 number, since 2×681866861² = 929884832259986642, 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 (681866881) 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, 58616 + ... + 69278.

It is an arithmetic number, because the mean of its divisors is an integer number (91817040).

Almost surely, 2^681866861 is an apocalyptic number.

It is an amenable number.

681866861 is a deficient number, since it is larger than the sum of its proper divisors (52669459).

681866861 is a wasteful number, since it uses less digits than its factorization.

681866861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15595.

The product of its digits is 663552, while the sum is 50.

The square root of 681866861 is about 26112.5805120827. The cubic root of 681866861 is about 880.1699314569.

The spelling of 681866861 in words is "six hundred eighty-one million, eight hundred sixty-six thousand, eight hundred sixty-one".