81115843 has 4 divisors (see below), whose sum is σ = 82841760. Its totient is φ = 79389928.

The previous prime is 81115829. The next prime is 81115873. The reversal of 81115843 is 34851118.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81115843 - 2¹³ = 81107651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81115873) 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, 862888 + ... + 862981.

It is an arithmetic number, because the mean of its divisors is an integer number (20710440).

Almost surely, 2^81115843 is an apocalyptic number.

81115843 is a deficient number, since it is larger than the sum of its proper divisors (1725917).

81115843 is a wasteful number, since it uses less digits than its factorization.

81115843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1725916.

The product of its digits is 3840, while the sum is 31.

The square root of 81115843 is about 9006.4334228373. The cubic root of 81115843 is about 432.8810376754.

The spelling of 81115843 in words is "eighty-one million, one hundred fifteen thousand, eight hundred forty-three".