16620209 has 2 divisors, whose sum is σ = 16620210. Its totient is φ = 16620208.

The previous prime is 16620173. The next prime is 16620223. The reversal of 16620209 is 90202661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11458225 + 5161984 = 3385^2 + 2272^2 .

It is a cyclic number.

It is not a de Polignac number, because 16620209 - 2¹² = 16616113 is a prime.

It is not a weakly prime, because it can be changed into another prime (16620229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8310104 + 8310105.

It is an arithmetic number, because the mean of its divisors is an integer number (8310105).

Almost surely, 2^16620209 is an apocalyptic number.

It is an amenable number.

16620209 is a deficient number, since it is larger than the sum of its proper divisors (1).

16620209 is an equidigital number, since it uses as much as digits as its factorization.

16620209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 16620209 is about 4076.7890551266. The cubic root of 16620209 is about 255.1989169430.

The spelling of 16620209 in words is "sixteen million, six hundred twenty thousand, two hundred nine".