21122213 has 4 divisors (see below), whose sum is σ = 24139680. Its totient is φ = 18104748.

The previous prime is 21122203. The next prime is 21122221. The reversal of 21122213 is 31222112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21122213 - 2⁴ = 21122197 is a prime.

It is a super-2 number, since 2×21122213² = 892295764034738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1508723 + ... + 1508736.

It is an arithmetic number, because the mean of its divisors is an integer number (6034920).

Almost surely, 2^21122213 is an apocalyptic number.

It is an amenable number.

21122213 is a deficient number, since it is larger than the sum of its proper divisors (3017467).

21122213 is an equidigital number, since it uses as much as digits as its factorization.

21122213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3017466.

The product of its digits is 48, while the sum is 14.

The square root of 21122213 is about 4595.8908820815. The cubic root of 21122213 is about 276.4265833876.

Adding to 21122213 its reverse (31222112), we get a palindrome (52344325).

The spelling of 21122213 in words is "twenty-one million, one hundred twenty-two thousand, two hundred thirteen".