81528228 has 24 divisors (see below), whose sum is σ = 211369760. Its totient is φ = 27176040.

The previous prime is 81528217. The next prime is 81528229. The reversal of 81528228 is 82282518.

It is a happy number.

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 = 81528192 and 81528201.

It is not an unprimeable number, because it can be changed into a prime (81528229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 377338 + ... + 377553.

Almost surely, 2^81528228 is an apocalyptic number.

It is an amenable number.

81528228 is an abundant number, since it is smaller than the sum of its proper divisors (129841532).

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

81528228 is a wasteful number, since it uses less digits than its factorization.

81528228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 754904 (or 754896 counting only the distinct ones).

The product of its digits is 20480, while the sum is 36.

The square root of 81528228 is about 9029.2983116076. The cubic root of 81528228 is about 433.6133729644.

The spelling of 81528228 in words is "eighty-one million, five hundred twenty-eight thousand, two hundred twenty-eight".