81185325618 has 32 divisors (see below), whose sum is σ = 169666099200. Its totient is φ = 25849143056.

The previous prime is 81185325589. The next prime is 81185325629. The reversal of 81185325618 is 81652358118.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309888 + ... + 508331.

It is an arithmetic number, because the mean of its divisors is an integer number (5302065600).

Almost surely, 2^81185325618 is an apocalyptic number.

81185325618 is an abundant number, since it is smaller than the sum of its proper divisors (88480773582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81185325618 is a wasteful number, since it uses less digits than its factorization.

81185325618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 818966.

The product of its digits is 460800, while the sum is 48.

The spelling of 81185325618 in words is "eighty-one billion, one hundred eighty-five million, three hundred twenty-five thousand, six hundred eighteen".