81197843 has 4 divisors (see below), whose sum is σ = 84728208. Its totient is φ = 77667480.

The previous prime is 81197819. The next prime is 81197863. The reversal of 81197843 is 34879118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34879118 = 2 ⋅17439559.

It is a cyclic number.

It is not a de Polignac number, because 81197843 - 2¹⁴ = 81181459 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81197843.

It is not an unprimeable number, because it can be changed into a prime (81197863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1765148 + ... + 1765193.

It is an arithmetic number, because the mean of its divisors is an integer number (21182052).

Almost surely, 2^81197843 is an apocalyptic number.

81197843 is a deficient number, since it is larger than the sum of its proper divisors (3530365).

81197843 is a wasteful number, since it uses less digits than its factorization.

81197843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3530364.

The product of its digits is 48384, while the sum is 41.

The square root of 81197843 is about 9010.9845743959. The cubic root of 81197843 is about 433.0268550211.

The spelling of 81197843 in words is "eighty-one million, one hundred ninety-seven thousand, eight hundred forty-three".