81281843 has 4 divisors (see below), whose sum is σ = 81582048. Its totient is φ = 80981640.

The previous prime is 81281833. The next prime is 81281869. The reversal of 81281843 is 34818218.

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 81281843 - 2¹⁶ = 81216307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81281813) 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, 149696 + ... + 150237.

It is an arithmetic number, because the mean of its divisors is an integer number (20395512).

Almost surely, 2^81281843 is an apocalyptic number.

81281843 is a deficient number, since it is larger than the sum of its proper divisors (300205).

81281843 is a wasteful number, since it uses less digits than its factorization.

81281843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300204.

The product of its digits is 12288, while the sum is 35.

The square root of 81281843 is about 9015.6443474662. The cubic root of 81281843 is about 433.1761271302.

The spelling of 81281843 in words is "eighty-one million, two hundred eighty-one thousand, eight hundred forty-three".