21216199 has 2 divisors, whose sum is σ = 21216200. Its totient is φ = 21216198.

The previous prime is 21216193. The next prime is 21216203. The reversal of 21216199 is 99161212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21216199 - 2³ = 21216191 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21216199.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21216191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608099 + 10608100.

It is an arithmetic number, because the mean of its divisors is an integer number (10608100).

Almost surely, 2^21216199 is an apocalyptic number.

21216199 is a deficient number, since it is larger than the sum of its proper divisors (1).

21216199 is an equidigital number, since it uses as much as digits as its factorization.

21216199 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 31.

The square root of 21216199 is about 4606.1045363734. The cubic root of 21216199 is about 276.8359753031.

The spelling of 21216199 in words is "twenty-one million, two hundred sixteen thousand, one hundred ninety-nine".