81446557812 has 24 divisors (see below), whose sum is σ = 190050067200. Its totient is φ = 27147695616.

The previous prime is 81446557811. The next prime is 81446557831. The reversal of 81446557812 is 21875564418.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81446557811) 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, 177364 + ... + 440852.

It is an arithmetic number, because the mean of its divisors is an integer number (7918752800).

Almost surely, 2^81446557812 is an apocalyptic number.

It is an amenable number.

81446557812 is an abundant number, since it is smaller than the sum of its proper divisors (108603509388).

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

81446557812 is a wasteful number, since it uses less digits than its factorization.

81446557812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289255 (or 289253 counting only the distinct ones).

The product of its digits is 2150400, while the sum is 51.

The spelling of 81446557812 in words is "eighty-one billion, four hundred forty-six million, five hundred fifty-seven thousand, eight hundred twelve".