81381252 has 48 divisors (see below), whose sum is σ = 194971392. Its totient is φ = 26407680.

The previous prime is 81381217. The next prime is 81381257. The reversal of 81381252 is 25218318.

It is not an unprimeable number, because it can be changed into a prime (81381257) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 176302 + ... + 176762.

It is an arithmetic number, because the mean of its divisors is an integer number (4061904).

Almost surely, 2^81381252 is an apocalyptic number.

It is an amenable number.

81381252 is an abundant number, since it is smaller than the sum of its proper divisors (113590140).

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

81381252 is a wasteful number, since it uses less digits than its factorization.

81381252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 828 (or 826 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 81381252 is about 9021.1558017806. The cubic root of 81381252 is about 433.3526489746.

The spelling of 81381252 in words is "eighty-one million, three hundred eighty-one thousand, two hundred fifty-two".