81783828 has 216 divisors, whose sum is σ = 266273280. Its totient is φ = 20684160.

The previous prime is 81783827. The next prime is 81783833. The reversal of 81783828 is 82838718.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81783827) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2638173 + ... + 2638203.

Almost surely, 2^81783828 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 81783828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133136640).

81783828 is an abundant number, since it is smaller than the sum of its proper divisors (184489452).

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

81783828 is a wasteful number, since it uses less digits than its factorization.

81783828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 91 counting only the distinct ones).

The product of its digits is 172032, while the sum is 45.

The square root of 81783828 is about 9043.4411592048. The cubic root of 81783828 is about 434.0660421771.

The spelling of 81783828 in words is "eighty-one million, seven hundred eighty-three thousand, eight hundred twenty-eight".