16221366409 has 2 divisors, whose sum is σ = 16221366410. Its totient is φ = 16221366408.

The previous prime is 16221366407. The next prime is 16221366437. The reversal of 16221366409 is 90466312261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9812883600 + 6408482809 = 99060^2 + 80053^2 .

It is a cyclic number.

It is not a de Polignac number, because 16221366409 - 2¹ = 16221366407 is a prime.

Together with 16221366407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (16221366407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8110683204 + 8110683205.

It is an arithmetic number, because the mean of its divisors is an integer number (8110683205).

Almost surely, 2^16221366409 is an apocalyptic number.

It is an amenable number.

16221366409 is a deficient number, since it is larger than the sum of its proper divisors (1).

16221366409 is an equidigital number, since it uses as much as digits as its factorization.

16221366409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 40.

The spelling of 16221366409 in words is "sixteen billion, two hundred twenty-one million, three hundred sixty-six thousand, four hundred nine".