81306299 has 2 divisors, whose sum is σ = 81306300. Its totient is φ = 81306298.

The previous prime is 81306271. The next prime is 81306317. The reversal of 81306299 is 99260318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81306299 - 2¹⁶ = 81240763 is a prime.

It is a super-2 number, since 2×81306299² = 13221428514154802, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81306259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40653149 + 40653150.

It is an arithmetic number, because the mean of its divisors is an integer number (40653150).

Almost surely, 2^81306299 is an apocalyptic number.

81306299 is a deficient number, since it is larger than the sum of its proper divisors (1).

81306299 is an equidigital number, since it uses as much as digits as its factorization.

81306299 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 81306299 is about 9017.0005545081. Note that the first 3 decimals coincide. The cubic root of 81306299 is about 433.2195673077.

The spelling of 81306299 in words is "eighty-one million, three hundred six thousand, two hundred ninety-nine".