81237811 has 2 divisors, whose sum is σ = 81237812. Its totient is φ = 81237810.

The previous prime is 81237803. The next prime is 81237823. The reversal of 81237811 is 11873218.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81237811 - 2³ = 81237803 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81937811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40618905 + 40618906.

It is an arithmetic number, because the mean of its divisors is an integer number (40618906).

Almost surely, 2^81237811 is an apocalyptic number.

81237811 is a deficient number, since it is larger than the sum of its proper divisors (1).

81237811 is an equidigital number, since it uses as much as digits as its factorization.

81237811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 31.

The square root of 81237811 is about 9013.2020392311. The cubic root of 81237811 is about 433.0978929443.

The spelling of 81237811 in words is "eighty-one million, two hundred thirty-seven thousand, eight hundred eleven".