81306259 has 2 divisors, whose sum is σ = 81306260. Its totient is φ = 81306258.

The previous prime is 81306191. The next prime is 81306271. The reversal of 81306259 is 95260318.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81306259 is a prime.

It is a super-2 number, since 2×81306259² = 13221415505150162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81306299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40653129 + 40653130.

It is an arithmetic number, because the mean of its divisors is an integer number (40653130).

Almost surely, 2^81306259 is an apocalyptic number.

81306259 is a deficient number, since it is larger than the sum of its proper divisors (1).

81306259 is an equidigital number, since it uses as much as digits as its factorization.

81306259 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 81306259 is about 9016.9983364754. The cubic root of 81306259 is about 433.2194962645.

The spelling of 81306259 in words is "eighty-one million, three hundred six thousand, two hundred fifty-nine".