81823913 has 2 divisors, whose sum is σ = 81823914. Its totient is φ = 81823912.

The previous prime is 81823871. The next prime is 81823927. The reversal of 81823913 is 31932818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75203584 + 6620329 = 8672^2 + 2573^2 .

It is a cyclic number.

It is not a de Polignac number, because 81823913 - 2⁸ = 81823657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81823813) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40911956 + 40911957.

It is an arithmetic number, because the mean of its divisors is an integer number (40911957).

Almost surely, 2^81823913 is an apocalyptic number.

It is an amenable number.

81823913 is a deficient number, since it is larger than the sum of its proper divisors (1).

81823913 is an equidigital number, since it uses as much as digits as its factorization.

81823913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 81823913 is about 9045.6571347802. The cubic root of 81823913 is about 434.1369473744.

The spelling of 81823913 in words is "eighty-one million, eight hundred twenty-three thousand, nine hundred thirteen".