81895279 has 2 divisors, whose sum is σ = 81895280. Its totient is φ = 81895278.

The previous prime is 81895277. The next prime is 81895283. The reversal of 81895279 is 97259818.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81895279 - 2¹ = 81895277 is a prime.

Together with 81895277, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81895277) 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, 40947639 + 40947640.

It is an arithmetic number, because the mean of its divisors is an integer number (40947640).

Almost surely, 2^81895279 is an apocalyptic number.

81895279 is a deficient number, since it is larger than the sum of its proper divisors (1).

81895279 is an equidigital number, since it uses as much as digits as its factorization.

81895279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 49.

The square root of 81895279 is about 9049.6010409299. The cubic root of 81895279 is about 434.2631273343.

The spelling of 81895279 in words is "eighty-one million, eight hundred ninety-five thousand, two hundred seventy-nine".