81842987 has 2 divisors, whose sum is σ = 81842988. Its totient is φ = 81842986.

The previous prime is 81842953. The next prime is 81842989. The reversal of 81842987 is 78924818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81842987 - 2⁶ = 81842923 is a prime.

Together with 81842989, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81842989) 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, 40921493 + 40921494.

It is an arithmetic number, because the mean of its divisors is an integer number (40921494).

Almost surely, 2^81842987 is an apocalyptic number.

81842987 is a deficient number, since it is larger than the sum of its proper divisors (1).

81842987 is an equidigital number, since it uses as much as digits as its factorization.

81842987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 258048, while the sum is 47.

The square root of 81842987 is about 9046.7113914394. The cubic root of 81842987 is about 434.1706786903.

The spelling of 81842987 in words is "eighty-one million, eight hundred forty-two thousand, nine hundred eighty-seven".