81009600 has 168 divisors, whose sum is σ = 303873408. Its totient is φ = 18508800.

The previous prime is 81009589. The next prime is 81009629. The reversal of 81009600 is 690018.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32395 + ... + 34805.

Almost surely, 2^81009600 is an apocalyptic number.

81009600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81009600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151936704).

81009600 is an abundant number, since it is smaller than the sum of its proper divisors (222863808).

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

81009600 is a wasteful number, since it uses less digits than its factorization.

81009600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2443 (or 2428 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 81009600 is about 9000.5333175318. The cubic root of 81009600 is about 432.6919637452.

Adding to 81009600 its reverse (690018), we get a palindrome (81699618).

The spelling of 81009600 in words is "eighty-one million, nine thousand, six hundred".