81224723 has 2 divisors, whose sum is σ = 81224724. Its totient is φ = 81224722.

The previous prime is 81224701. The next prime is 81224747. The reversal of 81224723 is 32742218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81224723 - 2⁶ = 81224659 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81224783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40612361 + 40612362.

It is an arithmetic number, because the mean of its divisors is an integer number (40612362).

Almost surely, 2^81224723 is an apocalyptic number.

81224723 is a deficient number, since it is larger than the sum of its proper divisors (1).

81224723 is an equidigital number, since it uses as much as digits as its factorization.

81224723 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5376, while the sum is 29.

The square root of 81224723 is about 9012.4759639069. The cubic root of 81224723 is about 433.0746332922.

The spelling of 81224723 in words is "eighty-one million, two hundred twenty-four thousand, seven hundred twenty-three".