21206219 has 2 divisors, whose sum is σ = 21206220. Its totient is φ = 21206218.

The previous prime is 21206189. The next prime is 21206233. The reversal of 21206219 is 91260212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21206219 - 2¹⁶ = 21140683 is a prime.

It is a super-2 number, since 2×21206219² = 899407448551922, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1342157 and since 21206219 and 1342157 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21206194 and 21206203.

It is not a weakly prime, because it can be changed into another prime (21206239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10603109 + 10603110.

It is an arithmetic number, because the mean of its divisors is an integer number (10603110).

Almost surely, 2^21206219 is an apocalyptic number.

21206219 is a deficient number, since it is larger than the sum of its proper divisors (1).

21206219 is an equidigital number, since it uses as much as digits as its factorization.

21206219 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21206219 is about 4605.0210640126. The cubic root of 21206219 is about 276.7925610492.

The spelling of 21206219 in words is "twenty-one million, two hundred six thousand, two hundred nineteen".