81635328 has 144 divisors (see below), whose sum is σ = 243603360. Its totient is φ = 26320896.

The previous prime is 81635327. The next prime is 81635341. The reversal of 81635328 is 82353618.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81635292 and 81635301.

It is not an unprimeable number, because it can be changed into a prime (81635321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 792525 + ... + 792627.

It is an arithmetic number, because the mean of its divisors is an integer number (1691690).

Almost surely, 2^81635328 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 81635328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121801680).

81635328 is an abundant number, since it is smaller than the sum of its proper divisors (161968032).

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

81635328 is a wasteful number, since it uses less digits than its factorization.

81635328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 151 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81635328 is about 9035.2270585747. The cubic root of 81635328 is about 433.8031627375.

It can be divided in two parts, 8 and 1635328, that added together give a triangular number (1635336 = T₁₈₀₈).

The spelling of 81635328 in words is "eighty-one million, six hundred thirty-five thousand, three hundred twenty-eight".