81148399 has 2 divisors, whose sum is σ = 81148400. Its totient is φ = 81148398.

The previous prime is 81148369. The next prime is 81148427. The reversal of 81148399 is 99384118.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81148399 - 2⁷ = 81148271 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81148369) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40574199 + 40574200.

It is an arithmetic number, because the mean of its divisors is an integer number (40574200).

Almost surely, 2^81148399 is an apocalyptic number.

81148399 is a deficient number, since it is larger than the sum of its proper divisors (1).

81148399 is an equidigital number, since it uses as much as digits as its factorization.

81148399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 43.

The square root of 81148399 is about 9008.2406162358. The cubic root of 81148399 is about 432.9389424758.

The spelling of 81148399 in words is "eighty-one million, one hundred forty-eight thousand, three hundred ninety-nine".