81325128 has 64 divisors (see below), whose sum is σ = 209664000. Its totient is φ = 26275392.

The previous prime is 81325117. The next prime is 81325129. The reversal of 81325128 is 82152318.

It is a super-2 number, since 2×81325128² = 13227552888432768, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81325095 and 81325104.

It is not an unprimeable number, because it can be changed into a prime (81325129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111501 + ... + 112227.

It is an arithmetic number, because the mean of its divisors is an integer number (3276000).

Almost surely, 2^81325128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81325128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104832000).

81325128 is an abundant number, since it is smaller than the sum of its proper divisors (128338872).

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

81325128 is a wasteful number, since it uses less digits than its factorization.

81325128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874 (or 870 counting only the distinct ones).

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

The square root of 81325128 is about 9018.0445774015. The cubic root of 81325128 is about 433.2530065440.

The spelling of 81325128 in words is "eighty-one million, three hundred twenty-five thousand, one hundred twenty-eight".