81212528 has 40 divisors (see below), whose sum is σ = 163843680. Its totient is φ = 38949120.

The previous prime is 81212507. The next prime is 81212561. The reversal of 81212528 is 82521218.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a self number, because there is not a number n which added to its sum of digits gives 81212528.

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 7 ways as a sum of consecutive naturals, for example, 83501 + ... + 84467.

It is an arithmetic number, because the mean of its divisors is an integer number (4096092).

Almost surely, 2^81212528 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 81212528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81921840).

81212528 is an abundant number, since it is smaller than the sum of its proper divisors (82631152).

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

81212528 is a wasteful number, since it uses less digits than its factorization.

81212528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185 (or 1179 counting only the distinct ones).

The product of its digits is 2560, while the sum is 29.

The square root of 81212528 is about 9011.7993763732. The cubic root of 81212528 is about 433.0529584077.

The spelling of 81212528 in words is "eighty-one million, two hundred twelve thousand, five hundred twenty-eight".