81630228 has 12 divisors (see below), whose sum is σ = 190470560. Its totient is φ = 27210072.

The previous prime is 81630181. The next prime is 81630247. The reversal of 81630228 is 82203618.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 81630195 and 81630204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3401248 + ... + 3401271.

Almost surely, 2^81630228 is an apocalyptic number.

It is an amenable number.

81630228 is an abundant number, since it is smaller than the sum of its proper divisors (108840332).

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

81630228 is a wasteful number, since it uses less digits than its factorization.

81630228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6802526 (or 6802524 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81630228 is about 9034.9448255095. The cubic root of 81630228 is about 433.7941288945.

The spelling of 81630228 in words is "eighty-one million, six hundred thirty thousand, two hundred twenty-eight".