81163500 has 96 divisors (see below), whose sum is σ = 257886720. Its totient is φ = 19672000.

The previous prime is 81163483. The next prime is 81163513. The reversal of 81163500 is 536118.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14041 + ... + 18959.

It is an arithmetic number, because the mean of its divisors is an integer number (2686320).

Almost surely, 2^81163500 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 81163500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128943360).

81163500 is an abundant number, since it is smaller than the sum of its proper divisors (176723220).

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

81163500 is a wasteful number, since it uses less digits than its factorization.

81163500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4952 (or 4940 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 81163500 is about 9009.0787542345. The cubic root of 81163500 is about 432.9657961806.

Adding to 81163500 its reverse (536118), we get a palindrome (81699618).

The spelling of 81163500 in words is "eighty-one million, one hundred sixty-three thousand, five hundred".