84278852521 has 2 divisors, whose sum is σ = 84278852522. Its totient is φ = 84278852520.

The previous prime is 84278852519. The next prime is 84278852527. The reversal of 84278852521 is 12525887248.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66183222121 + 18095630400 = 257261^2 + 134520^2 .

It is a cyclic number.

It is not a de Polignac number, because 84278852521 - 2¹ = 84278852519 is a prime.

Together with 84278852519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (84278852527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42139426260 + 42139426261.

It is an arithmetic number, because the mean of its divisors is an integer number (42139426261).

Almost surely, 2^84278852521 is an apocalyptic number.

It is an amenable number.

84278852521 is a deficient number, since it is larger than the sum of its proper divisors (1).

84278852521 is an equidigital number, since it uses as much as digits as its factorization.

84278852521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2867200, while the sum is 52.

The spelling of 84278852521 in words is "eighty-four billion, two hundred seventy-eight million, eight hundred fifty-two thousand, five hundred twenty-one".