81038521 has 2 divisors, whose sum is σ = 81038522. Its totient is φ = 81038520.

The previous prime is 81038497. The next prime is 81038539. The reversal of 81038521 is 12583018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69889600 + 11148921 = 8360^2 + 3339^2 .

It is a cyclic number.

It is not a de Polignac number, because 81038521 - 2²⁵ = 47484089 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 81038521.

It is not a weakly prime, because it can be changed into another prime (81032521) 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, 40519260 + 40519261.

It is an arithmetic number, because the mean of its divisors is an integer number (40519261).

Almost surely, 2^81038521 is an apocalyptic number.

It is an amenable number.

81038521 is a deficient number, since it is larger than the sum of its proper divisors (1).

81038521 is an equidigital number, since it uses as much as digits as its factorization.

81038521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 81038521 is about 9002.1398011806. The cubic root of 81038521 is about 432.7434489823.

The spelling of 81038521 in words is "eighty-one million, thirty-eight thousand, five hundred twenty-one".