81947443 has 8 divisors (see below), whose sum is σ = 83437200. Its totient is φ = 80471040.

The previous prime is 81947431. The next prime is 81947447. The reversal of 81947443 is 34474918.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81947443 - 2²⁵ = 48393011 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81947396 and 81947405.

It is not an unprimeable number, because it can be changed into a prime (81947447) 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, 9483 + ... + 15931.

It is an arithmetic number, because the mean of its divisors is an integer number (10429650).

Almost surely, 2^81947443 is an apocalyptic number.

81947443 is a deficient number, since it is larger than the sum of its proper divisors (1489757).

81947443 is a wasteful number, since it uses less digits than its factorization.

81947443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6677.

The product of its digits is 96768, while the sum is 40.

The square root of 81947443 is about 9052.4826981331. The cubic root of 81947443 is about 434.3553104820.

The spelling of 81947443 in words is "eighty-one million, nine hundred forty-seven thousand, four hundred forty-three".