84689579521 has 2 divisors, whose sum is σ = 84689579522. Its totient is φ = 84689579520.

The previous prime is 84689579497. The next prime is 84689579537. The reversal of 84689579521 is 12597598648.

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., 78363604225 + 6325975296 = 279935^2 + 79536^2 .

It is a cyclic number.

It is not a de Polignac number, because 84689579521 - 2¹¹ = 84689577473 is a prime.

It is not a weakly prime, because it can be changed into another prime (84689574521) 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, 42344789760 + 42344789761.

It is an arithmetic number, because the mean of its divisors is an integer number (42344789761).

Almost surely, 2^84689579521 is an apocalyptic number.

It is an amenable number.

84689579521 is a deficient number, since it is larger than the sum of its proper divisors (1).

84689579521 is an equidigital number, since it uses as much as digits as its factorization.

84689579521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43545600, while the sum is 64.

The spelling of 84689579521 in words is "eighty-four billion, six hundred eighty-nine million, five hundred seventy-nine thousand, five hundred twenty-one".