81105247 has 2 divisors, whose sum is σ = 81105248. Its totient is φ = 81105246.

The previous prime is 81105239. The next prime is 81105259. The reversal of 81105247 is 74250118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81105247 - 2³ = 81105239 is a prime.

It is a super-2 number, since 2×81105247² = 13156122181862018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81105287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40552623 + 40552624.

It is an arithmetic number, because the mean of its divisors is an integer number (40552624).

Almost surely, 2^81105247 is an apocalyptic number.

81105247 is a deficient number, since it is larger than the sum of its proper divisors (1).

81105247 is an equidigital number, since it uses as much as digits as its factorization.

81105247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 81105247 is about 9005.8451574519. The cubic root of 81105247 is about 432.8621880605.

The spelling of 81105247 in words is "eighty-one million, one hundred five thousand, two hundred forty-seven".