15664217 has 2 divisors, whose sum is σ = 15664218. Its totient is φ = 15664216.

The previous prime is 15664213. The next prime is 15664223. The reversal of 15664217 is 71246651.

15664217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7958041 + 7706176 = 2821^2 + 2776^2 .

It is a cyclic number.

It is not a de Polignac number, because 15664217 - 2² = 15664213 is a prime.

It is not a weakly prime, because it can be changed into another prime (15664211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7832108 + 7832109.

It is an arithmetic number, because the mean of its divisors is an integer number (7832109).

Almost surely, 2^15664217 is an apocalyptic number.

It is an amenable number.

15664217 is a deficient number, since it is larger than the sum of its proper divisors (1).

15664217 is an equidigital number, since it uses as much as digits as its factorization.

15664217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 32.

The square root of 15664217 is about 3957.8045681918. The cubic root of 15664217 is about 250.2089825898.

The spelling of 15664217 in words is "fifteen million, six hundred sixty-four thousand, two hundred seventeen".