82128521 has 2 divisors, whose sum is σ = 82128522. Its totient is φ = 82128520.

The previous prime is 82128511. The next prime is 82128523. The reversal of 82128521 is 12582128.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53655625 + 28472896 = 7325^2 + 5336^2 .

It is a cyclic number.

It is not a de Polignac number, because 82128521 - 2¹⁰ = 82127497 is a prime.

Together with 82128523, 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 (82128523) 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, 41064260 + 41064261.

It is an arithmetic number, because the mean of its divisors is an integer number (41064261).

Almost surely, 2^82128521 is an apocalyptic number.

It is an amenable number.

82128521 is a deficient number, since it is larger than the sum of its proper divisors (1).

82128521 is an equidigital number, since it uses as much as digits as its factorization.

82128521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2560, while the sum is 29.

The square root of 82128521 is about 9062.4787448027. The cubic root of 82128521 is about 434.6750045317.

The spelling of 82128521 in words is "eighty-two million, one hundred twenty-eight thousand, five hundred twenty-one".