81636263618 has 64 divisors (see below), whose sum is σ = 166516922880. Its totient is φ = 29074332672.

The previous prime is 81636263593. The next prime is 81636263651.

81636263618 is nontrivially palindromic in base 10.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 502433 + ... + 644756.

It is an arithmetic number, because the mean of its divisors is an integer number (2601826920).

Almost surely, 2^81636263618 is an apocalyptic number.

81636263618 is an abundant number, since it is smaller than the sum of its proper divisors (84880659262).

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

81636263618 is a wasteful number, since it uses less digits than its factorization.

81636263618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1147251.

The product of its digits is 1492992, while the sum is 50.

The spelling of 81636263618 in words is "eighty-one billion, six hundred thirty-six million, two hundred sixty-three thousand, six hundred eighteen".