81099228 has 24 divisors (see below), whose sum is σ = 216264832. Its totient is φ = 23171184.

The previous prime is 81099211. The next prime is 81099233. The reversal of 81099228 is 82299018.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 482650 + ... + 482817.

Almost surely, 2^81099228 is an apocalyptic number.

It is an amenable number.

81099228 is an abundant number, since it is smaller than the sum of its proper divisors (135165604).

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

81099228 is a wasteful number, since it uses less digits than its factorization.

81099228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 965481 (or 965479 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 81099228 is about 9005.5109793948. The cubic root of 81099228 is about 432.8514799084.

The spelling of 81099228 in words is "eighty-one million, ninety-nine thousand, two hundred twenty-eight".