81650409618 has 16 divisors (see below), whose sum is σ = 163936234080. Its totient is φ = 27110900736.

The previous prime is 81650409613. The next prime is 81650409619. The reversal of 81650409618 is 81690405618.

It is not an unprimeable number, because it can be changed into a prime (81650409613) 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, 26473948 + ... + 26477031.

It is an arithmetic number, because the mean of its divisors is an integer number (10246014630).

Almost surely, 2^81650409618 is an apocalyptic number.

81650409618 is an abundant number, since it is smaller than the sum of its proper divisors (82285824462).

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

81650409618 is a wasteful number, since it uses less digits than its factorization.

81650409618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52951241.

The product of its (nonzero) digits is 414720, while the sum is 48.

The spelling of 81650409618 in words is "eighty-one billion, six hundred fifty million, four hundred nine thousand, six hundred eighteen".