81525211 has 2 divisors, whose sum is σ = 81525212. Its totient is φ = 81525210.

The previous prime is 81525209. The next prime is 81525247. The reversal of 81525211 is 11252518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81525211 - 2¹ = 81525209 is a prime.

Together with 81525209, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (81525511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40762605 + 40762606.

It is an arithmetic number, because the mean of its divisors is an integer number (40762606).

Almost surely, 2^81525211 is an apocalyptic number.

81525211 is a deficient number, since it is larger than the sum of its proper divisors (1).

81525211 is an equidigital number, since it uses as much as digits as its factorization.

81525211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 800, while the sum is 25.

The square root of 81525211 is about 9029.1312428162. The cubic root of 81525211 is about 433.6080241925.

Adding to 81525211 its reverse (11252518), we get a palindrome (92777729).

The spelling of 81525211 in words is "eighty-one million, five hundred twenty-five thousand, two hundred eleven".