81573228 has 36 divisors (see below), whose sum is σ = 224945448. Its totient is φ = 24719040.

The previous prime is 81573199. The next prime is 81573253. The reversal of 81573228 is 82237518.

81573228 is a `hidden beast` number, since 81 + 573 + 2 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

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 = 81573192 and 81573201.

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, 102601 + ... + 103392.

Almost surely, 2^81573228 is an apocalyptic number.

It is an amenable number.

81573228 is an abundant number, since it is smaller than the sum of its proper divisors (143372220).

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

81573228 is a wasteful number, since it uses less digits than its factorization.

81573228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206014 (or 206009 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 81573228 is about 9031.7898558370. The cubic root of 81573228 is about 433.6931368013.

The spelling of 81573228 in words is "eighty-one million, five hundred seventy-three thousand, two hundred twenty-eight".