81730628 has 72 divisors (see below), whose sum is σ = 185582880. Its totient is φ = 31207680.

The previous prime is 81730567. The next prime is 81730657. The reversal of 81730628 is 82603718.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62663 + ... + 63953.

It is an arithmetic number, because the mean of its divisors is an integer number (2577540).

Almost surely, 2^81730628 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81730628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92791440).

81730628 is an abundant number, since it is smaller than the sum of its proper divisors (103852252).

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

81730628 is a wasteful number, since it uses less digits than its factorization.

81730628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1345 (or 1336 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 81730628 is about 9040.4993224932. The cubic root of 81730628 is about 433.9719024474.

The spelling of 81730628 in words is "eighty-one million, seven hundred thirty thousand, six hundred twenty-eight".