81532900 has 36 divisors (see below), whose sum is σ = 178933860. Its totient is φ = 32243200.

The previous prime is 81532879. The next prime is 81532909. The reversal of 81532900 is 923518.

It can be written as a sum of positive squares in 6 ways, for example, as 11943936 + 69588964 = 3456^2 + 8342^2 .

It is a super-2 number, since 2×81532900² = 13295227564820000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81532909) 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, 4320 + ... + 13480.

It is an arithmetic number, because the mean of its divisors is an integer number (4970385).

Almost surely, 2^81532900 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 81532900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89466930).

81532900 is an abundant number, since it is smaller than the sum of its proper divisors (97400960).

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

81532900 is a wasteful number, since it uses less digits than its factorization.

81532900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9264 (or 9257 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 81532900 is about 9029.5570212497. The cubic root of 81532900 is about 433.6216555884.

It can be divided in two parts, 81 and 532900, that multiplied together give a square (43164900 = 6570²).

The spelling of 81532900 in words is "eighty-one million, five hundred thirty-two thousand, nine hundred".