81259240 has 32 divisors (see below), whose sum is σ = 186727680. Its totient is φ = 31811392.

The previous prime is 81259187. The next prime is 81259267. The reversal of 81259240 is 4295218.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19732 + ... + 23491.

It is an arithmetic number, because the mean of its divisors is an integer number (5835240).

Almost surely, 2^81259240 is an apocalyptic number.

It is an amenable number.

81259240 is an abundant number, since it is smaller than the sum of its proper divisors (105468440).

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

81259240 is a wasteful number, since it uses less digits than its factorization.

81259240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43281 (or 43277 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 81259240 is about 9014.3907170701. The cubic root of 81259240 is about 433.1359706108.

It can be divided in two parts, 81 and 259240, that multiplied together give a triangular number (20998440 = T₆₄₈₀).

The spelling of 81259240 in words is "eighty-one million, two hundred fifty-nine thousand, two hundred forty".