81607087861 has 16 divisors (see below), whose sum is σ = 93081293424. Its totient is φ = 70877850624.

The previous prime is 81607087847. The next prime is 81607087889. The reversal of 81607087861 is 16878070618.

It can be written as a sum of positive squares in 8 ways, for example, as 19521398961 + 62085688900 = 139719^2 + 249170^2 .

It is a cyclic number.

It is not a de Polignac number, because 81607087861 - 2⁷ = 81607087733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81607087799 and 81607087808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81607487861) 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, 734191 + ... + 838003.

It is an arithmetic number, because the mean of its divisors is an integer number (5817580839).

Almost surely, 2^81607087861 is an apocalyptic number.

It is an amenable number.

81607087861 is a deficient number, since it is larger than the sum of its proper divisors (11474205563).

81607087861 is a wasteful number, since it uses less digits than its factorization.

81607087861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107400.

The product of its (nonzero) digits is 903168, while the sum is 52.

The spelling of 81607087861 in words is "eighty-one billion, six hundred seven million, eighty-seven thousand, eight hundred sixty-one".