81730228 has 12 divisors (see below), whose sum is σ = 143117380. Its totient is φ = 40839552.

The previous prime is 81730223. The next prime is 81730249. The reversal of 81730228 is 82203718.

It can be written as a sum of positive squares in 2 ways, for example, as 8832784 + 72897444 = 2972^2 + 8538^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81730228.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81730223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2038 + ... + 12946.

Almost surely, 2^81730228 is an apocalyptic number.

It is an amenable number.

81730228 is a deficient number, since it is larger than the sum of its proper divisors (61387152).

81730228 is a wasteful number, since it uses less digits than its factorization.

81730228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12786 (or 12784 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 81730228 is about 9040.4771997943. The cubic root of 81730228 is about 433.9711944751.

The spelling of 81730228 in words is "eighty-one million, seven hundred thirty thousand, two hundred twenty-eight".