81571228 has 6 divisors (see below), whose sum is σ = 142749656. Its totient is φ = 40785612.

The previous prime is 81571183. The next prime is 81571247. The reversal of 81571228 is 82217518.

It is a super-3 number, since 3×81571228³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81571193 and 81571202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10196400 + ... + 10196407.

Almost surely, 2^81571228 is an apocalyptic number.

It is an amenable number.

81571228 is a deficient number, since it is larger than the sum of its proper divisors (61178428).

81571228 is a wasteful number, since it uses less digits than its factorization.

81571228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20392811 (or 20392809 counting only the distinct ones).

The product of its digits is 8960, while the sum is 34.

The square root of 81571228 is about 9031.6791351332. The cubic root of 81571228 is about 433.6895923649.

The spelling of 81571228 in words is "eighty-one million, five hundred seventy-one thousand, two hundred twenty-eight".