81886249 has 2 divisors, whose sum is σ = 81886250. Its totient is φ = 81886248.

The previous prime is 81886247. The next prime is 81886253. The reversal of 81886249 is 94268818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58798224 + 23088025 = 7668^2 + 4805^2 .

It is a cyclic number.

It is not a de Polignac number, because 81886249 - 2¹ = 81886247 is a prime.

Together with 81886247, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81886199 and 81886208.

It is not a weakly prime, because it can be changed into another prime (81886247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40943124 + 40943125.

It is an arithmetic number, because the mean of its divisors is an integer number (40943125).

Almost surely, 2^81886249 is an apocalyptic number.

It is an amenable number.

81886249 is a deficient number, since it is larger than the sum of its proper divisors (1).

81886249 is an equidigital number, since it uses as much as digits as its factorization.

81886249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 221184, while the sum is 46.

The square root of 81886249 is about 9049.1021101544. The cubic root of 81886249 is about 434.2471657297.

The spelling of 81886249 in words is "eighty-one million, eight hundred eighty-six thousand, two hundred forty-nine".