81197872 has 40 divisors (see below), whose sum is σ = 182345472. Its totient is φ = 34305600.

The previous prime is 81197863. The next prime is 81197873. The reversal of 81197872 is 27879118.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81197873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2847 + ... + 13057.

Almost surely, 2^81197872 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 81197872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91172736).

81197872 is an abundant number, since it is smaller than the sum of its proper divisors (101147600).

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

81197872 is a wasteful number, since it uses less digits than its factorization.

81197872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10297 (or 10291 counting only the distinct ones).

The product of its digits is 56448, while the sum is 43.

The square root of 81197872 is about 9010.9861835428. The cubic root of 81197872 is about 433.0269065733.

The spelling of 81197872 in words is "eighty-one million, one hundred ninety-seven thousand, eight hundred seventy-two".