81229500 has 192 divisors, whose sum is σ = 287239680. Its totient is φ = 19656000.

The previous prime is 81229481. The next prime is 81229529. The reversal of 81229500 is 592218.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 148227 + ... + 148773.

It is an arithmetic number, because the mean of its divisors is an integer number (1496040).

Almost surely, 2^81229500 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 81229500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143619840).

81229500 is an abundant number, since it is smaller than the sum of its proper divisors (206010180).

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

81229500 is a wasteful number, since it uses less digits than its factorization.

81229500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 568 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 81229500 is about 9012.7409815217. The cubic root of 81229500 is about 433.0831231415.

The spelling of 81229500 in words is "eighty-one million, two hundred twenty-nine thousand, five hundred".