81528732 has 72 divisors (see below), whose sum is σ = 211341312. Its totient is φ = 26493600.

The previous prime is 81528703. The next prime is 81528761. The reversal of 81528732 is 23782518.

It is an interprime number because it is at equal distance from previous prime (81528703) and next prime (81528761).

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

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, 426757 + ... + 426947.

It is an arithmetic number, because the mean of its divisors is an integer number (2935296).

Almost surely, 2^81528732 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 81528732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105670656).

81528732 is an abundant number, since it is smaller than the sum of its proper divisors (129812580).

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

81528732 is a wasteful number, since it uses less digits than its factorization.

81528732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439 (or 434 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 81528732 is about 9029.3262207099. The cubic root of 81528732 is about 433.6142664818.

The spelling of 81528732 in words is "eighty-one million, five hundred twenty-eight thousand, seven hundred thirty-two".