81447635760 has 80 divisors (see below), whose sum is σ = 252540857184. Its totient is φ = 21714794496.

The previous prime is 81447635707. The next prime is 81447635767. The reversal of 81447635760 is 6753674418.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81447635767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1193934 + ... + 1260306.

Almost surely, 2^81447635760 is an apocalyptic number.

81447635760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81447635760 is an abundant number, since it is smaller than the sum of its proper divisors (171093221424).

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

81447635760 is a wasteful number, since it uses less digits than its factorization.

81447635760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71502 (or 71496 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 51.

The spelling of 81447635760 in words is "eighty-one billion, four hundred forty-seven million, six hundred thirty-five thousand, seven hundred sixty".