21426211 has 4 divisors (see below), whose sum is σ = 21499632. Its totient is φ = 21352792.

The previous prime is 21426203. The next prime is 21426217. The reversal of 21426211 is 11262412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21426211 - 2³ = 21426203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21426217) 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 in 3 ways as a sum of consecutive naturals, for example, 36271 + ... + 36856.

It is an arithmetic number, because the mean of its divisors is an integer number (5374908).

Almost surely, 2^21426211 is an apocalyptic number.

21426211 is a deficient number, since it is larger than the sum of its proper divisors (73421).

21426211 is an equidigital number, since it uses as much as digits as its factorization.

21426211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73420.

The product of its digits is 192, while the sum is 19.

The square root of 21426211 is about 4628.8455364162. The cubic root of 21426211 is about 277.7464131639.

Adding to 21426211 its reverse (11262412), we get a palindrome (32688623).

The spelling of 21426211 in words is "twenty-one million, four hundred twenty-six thousand, two hundred eleven".