8521493809 has 2 divisors, whose sum is σ = 8521493810. Its totient is φ = 8521493808.

The previous prime is 8521493779. The next prime is 8521493821. The reversal of 8521493809 is 9083941258.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4819136400 + 3702357409 = 69420^2 + 60847^2 .

It is a cyclic number.

It is not a de Polignac number, because 8521493809 - 2¹⁵ = 8521461041 is a prime.

It is not a weakly prime, because it can be changed into another prime (8521493909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4260746904 + 4260746905.

It is an arithmetic number, because the mean of its divisors is an integer number (4260746905).

Almost surely, 2^8521493809 is an apocalyptic number.

It is an amenable number.

8521493809 is a deficient number, since it is larger than the sum of its proper divisors (1).

8521493809 is an equidigital number, since it uses as much as digits as its factorization.

8521493809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 622080, while the sum is 49.

The square root of 8521493809 is about 92311.9375216445. The cubic root of 8521493809 is about 2042.5463053013.

The spelling of 8521493809 in words is "eight billion, five hundred twenty-one million, four hundred ninety-three thousand, eight hundred nine".