81529128 has 48 divisors (see below), whose sum is σ = 222300000. Its totient is φ = 26992800.

The previous prime is 81529103. The next prime is 81529141. The reversal of 81529128 is 82192518.

81529128 is a `hidden beast` number, since 8 + 1 + 529 + 128 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81529092 and 81529101.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7123 + ... + 14621.

It is an arithmetic number, because the mean of its divisors is an integer number (4631250).

Almost surely, 2^81529128 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 81529128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111150000).

81529128 is an abundant number, since it is smaller than the sum of its proper divisors (140770872).

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

81529128 is a wasteful number, since it uses less digits than its factorization.

81529128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7662 (or 7655 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 81529128 is about 9029.3481492298. The cubic root of 81529128 is about 433.6149685287.

The spelling of 81529128 in words is "eighty-one million, five hundred twenty-nine thousand, one hundred twenty-eight".