81339956464 has 80 divisors (see below), whose sum is σ = 171308591104. Its totient is φ = 37191571200.

The previous prime is 81339956447. The next prime is 81339956501. The reversal of 81339956464 is 46465993318.

It is a junction number, because it is equal to n+sod(n) for n = 81339956399 and 81339956408.

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 9782869 + ... + 9791179.

Almost surely, 2^81339956464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81339956464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85654295552).

81339956464 is an abundant number, since it is smaller than the sum of its proper divisors (89968634640).

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

81339956464 is a wasteful number, since it uses less digits than its factorization.

81339956464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8766 (or 8760 counting only the distinct ones).

The product of its digits is 16796160, while the sum is 58.

The spelling of 81339956464 in words is "eighty-one billion, three hundred thirty-nine million, nine hundred fifty-six thousand, four hundred sixty-four".