81653843 has 4 divisors (see below), whose sum is σ = 82010640. Its totient is φ = 81297048.

The previous prime is 81653833. The next prime is 81653863. The reversal of 81653843 is 34835618.

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 81653843 - 2⁴ = 81653827 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81653797 and 81653806.

It is not an unprimeable number, because it can be changed into a prime (81653813) 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, 178055 + ... + 178512.

It is an arithmetic number, because the mean of its divisors is an integer number (20502660).

Almost surely, 2^81653843 is an apocalyptic number.

81653843 is a deficient number, since it is larger than the sum of its proper divisors (356797).

81653843 is a wasteful number, since it uses less digits than its factorization.

81653843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356796.

The product of its digits is 69120, while the sum is 38.

The square root of 81653843 is about 9036.2516011895. The cubic root of 81653843 is about 433.8359559682.

The spelling of 81653843 in words is "eighty-one million, six hundred fifty-three thousand, eight hundred forty-three".