21116213 has 2 divisors, whose sum is σ = 21116214. Its totient is φ = 21116212.

The previous prime is 21116209. The next prime is 21116219. The reversal of 21116213 is 31261112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16459249 + 4656964 = 4057^2 + 2158^2 .

It is a cyclic number.

It is not a de Polignac number, because 21116213 - 2² = 21116209 is a prime.

It is a super-2 number, since 2×21116213² = 891788902922738, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21116191 and 21116200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21116219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10558106 + 10558107.

It is an arithmetic number, because the mean of its divisors is an integer number (10558107).

Almost surely, 2^21116213 is an apocalyptic number.

It is an amenable number.

21116213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21116213 is an equidigital number, since it uses as much as digits as its factorization.

21116213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 17.

The square root of 21116213 is about 4595.2380787071. The cubic root of 21116213 is about 276.4004068917.

Adding to 21116213 its reverse (31261112), we get a palindrome (52377325).

The spelling of 21116213 in words is "twenty-one million, one hundred sixteen thousand, two hundred thirteen".