81542248172 has 48 divisors (see below), whose sum is σ = 177932498688. Its totient is φ = 31765753920.

The previous prime is 81542248171. The next prime is 81542248201. The reversal of 81542248172 is 27184224518.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (81542248171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4273838 + ... + 4292874.

It is an arithmetic number, because the mean of its divisors is an integer number (3706927056).

Almost surely, 2^81542248172 is an apocalyptic number.

It is an amenable number.

81542248172 is an abundant number, since it is smaller than the sum of its proper divisors (96390250516).

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

81542248172 is a wasteful number, since it uses less digits than its factorization.

81542248172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32966 (or 32964 counting only the distinct ones).

The product of its digits is 286720, while the sum is 44.

The spelling of 81542248172 in words is "eighty-one billion, five hundred forty-two million, two hundred forty-eight thousand, one hundred seventy-two".