81488140 has 24 divisors (see below), whose sum is σ = 181192032. Its totient is φ = 30677760.

The previous prime is 81488117. The next prime is 81488159. The reversal of 81488140 is 4188418.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 81488096 and 81488105.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119496 + ... + 120175.

It is an arithmetic number, because the mean of its divisors is an integer number (7549668).

Almost surely, 2^81488140 is an apocalyptic number.

It is an amenable number.

81488140 is an abundant number, since it is smaller than the sum of its proper divisors (99703892).

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

81488140 is a wasteful number, since it uses less digits than its factorization.

81488140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239697 (or 239695 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 34.

The square root of 81488140 is about 9027.0781540873. The cubic root of 81488140 is about 433.5422910697.

The spelling of 81488140 in words is "eighty-one million, four hundred eighty-eight thousand, one hundred forty".