81264118618 has 4 divisors (see below), whose sum is σ = 121896177930. Its totient is φ = 40632059308.

The previous prime is 81264118601. The next prime is 81264118619. The reversal of 81264118618 is 81681146218.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 74694529809 + 6569588809 = 273303^2 + 81053^2 .

It is not an unprimeable number, because it can be changed into a prime (81264118619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20316029653 + ... + 20316029656.

Almost surely, 2^81264118618 is an apocalyptic number.

81264118618 is a deficient number, since it is larger than the sum of its proper divisors (40632059312).

81264118618 is a wasteful number, since it uses less digits than its factorization.

81264118618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40632059311.

The product of its digits is 147456, while the sum is 46.

The spelling of 81264118618 in words is "eighty-one billion, two hundred sixty-four million, one hundred eighteen thousand, six hundred eighteen".