81596969618 has 8 divisors (see below), whose sum is σ = 123029628348. Its totient is φ = 40587093504.

The previous prime is 81596969617. The next prime is 81596969653. The reversal of 81596969618 is 81696969518.

It can be written as a sum of positive squares in 2 ways, for example, as 77783536609 + 3813433009 = 278897^2 + 61753^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81596969617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105695171 + ... + 105695942.

Almost surely, 2^81596969618 is an apocalyptic number.

81596969618 is a deficient number, since it is larger than the sum of its proper divisors (41432658730).

81596969618 is a wasteful number, since it uses less digits than its factorization.

81596969618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211391308.

The product of its digits is 50388480, while the sum is 68.

The spelling of 81596969618 in words is "eighty-one billion, five hundred ninety-six million, nine hundred sixty-nine thousand, six hundred eighteen".