81521528 has 32 divisors (see below), whose sum is σ = 176560560. Its totient is φ = 34874880.

The previous prime is 81521527. The next prime is 81521543. The reversal of 81521528 is 82512518.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81521494 and 81521503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81521527) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 25751 + ... + 28742.

Almost surely, 2^81521528 is an apocalyptic number.

81521528 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

81521528 is an abundant number, since it is smaller than the sum of its proper divisors (95039032).

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

81521528 is a wasteful number, since it uses less digits than its factorization.

81521528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54527 (or 54523 counting only the distinct ones).

The product of its digits is 6400, while the sum is 32.

The square root of 81521528 is about 9028.9272895511. The cubic root of 81521528 is about 433.6014945052.

The spelling of 81521528 in words is "eighty-one million, five hundred twenty-one thousand, five hundred twenty-eight".