81015228 has 132 divisors (see below), whose sum is σ = 248004400. Its totient is φ = 23147208.

The previous prime is 81015199. The next prime is 81015257. The reversal of 81015228 is 82251018.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is an interprime number because it is at equal distance from previous prime (81015199) and next prime (81015257).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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 43 ways as a sum of consecutive naturals, for example, 11573601 + ... + 11573607.

Almost surely, 2^81015228 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 81015228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124002200).

81015228 is an abundant number, since it is smaller than the sum of its proper divisors (166989172).

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

81015228 is an frugal number, since it uses more digits than its factorization.

81015228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55 (or 12 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 81015228 is about 9000.8459602417. The cubic root of 81015228 is about 432.7019836852.

The spelling of 81015228 in words is "eighty-one million, fifteen thousand, two hundred twenty-eight".