81281243 has 2 divisors, whose sum is σ = 81281244. Its totient is φ = 81281242.

The previous prime is 81281231. The next prime is 81281257. The reversal of 81281243 is 34218218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81281243 - 2⁴ = 81281227 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81281203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40640621 + 40640622.

It is an arithmetic number, because the mean of its divisors is an integer number (40640622).

Almost surely, 2^81281243 is an apocalyptic number.

81281243 is a deficient number, since it is larger than the sum of its proper divisors (1).

81281243 is an equidigital number, since it uses as much as digits as its factorization.

81281243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3072, while the sum is 29.

The square root of 81281243 is about 9015.6110719130. The cubic root of 81281243 is about 433.1750612656.

The spelling of 81281243 in words is "eighty-one million, two hundred eighty-one thousand, two hundred forty-three".