81032521 has 2 divisors, whose sum is σ = 81032522. Its totient is φ = 81032520.

The previous prime is 81032449. The next prime is 81032527. The reversal of 81032521 is 12523018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80802121 + 230400 = 8989^2 + 480^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81032521 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 81032492 and 81032501.

It is not a weakly prime, because it can be changed into another prime (81032527) 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, 40516260 + 40516261.

It is an arithmetic number, because the mean of its divisors is an integer number (40516261).

Almost surely, 2^81032521 is an apocalyptic number.

It is an amenable number.

81032521 is a deficient number, since it is larger than the sum of its proper divisors (1).

81032521 is an equidigital number, since it uses as much as digits as its factorization.

81032521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 81032521 is about 9001.8065409117. The cubic root of 81032521 is about 432.7327687744.

Adding to 81032521 its reverse (12523018), we get a palindrome (93555539).

The spelling of 81032521 in words is "eighty-one million, thirty-two thousand, five hundred twenty-one".