81237823 has 2 divisors, whose sum is σ = 81237824. Its totient is φ = 81237822.

The previous prime is 81237811. The next prime is 81237857. The reversal of 81237823 is 32873218.

It is an a-pointer prime, because the next prime (81237857) can be obtained adding 81237823 to its sum of digits (34).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81237823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81237803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40618911 + 40618912.

It is an arithmetic number, because the mean of its divisors is an integer number (40618912).

Almost surely, 2^81237823 is an apocalyptic number.

81237823 is a deficient number, since it is larger than the sum of its proper divisors (1).

81237823 is an equidigital number, since it uses as much as digits as its factorization.

81237823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 34.

The square root of 81237823 is about 9013.2027049213. The cubic root of 81237823 is about 433.0979142693.

The spelling of 81237823 in words is "eighty-one million, two hundred thirty-seven thousand, eight hundred twenty-three".