81624017 has 2 divisors, whose sum is σ = 81624018. Its totient is φ = 81624016.

The previous prime is 81623999. The next prime is 81624047. The reversal of 81624017 is 71042618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45576001 + 36048016 = 6751^2 + 6004^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81624017 is a prime.

It is not a weakly prime, because it can be changed into another prime (81624047) 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, 40812008 + 40812009.

It is an arithmetic number, because the mean of its divisors is an integer number (40812009).

Almost surely, 2^81624017 is an apocalyptic number.

It is an amenable number.

81624017 is a deficient number, since it is larger than the sum of its proper divisors (1).

81624017 is an equidigital number, since it uses as much as digits as its factorization.

81624017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 81624017 is about 9034.6010980010. The cubic root of 81624017 is about 433.7831265827.

The spelling of 81624017 in words is "eighty-one million, six hundred twenty-four thousand, seventeen".