21214121 has 4 divisors (see below), whose sum is σ = 21278544. Its totient is φ = 21149700.

The previous prime is 21214117. The next prime is 21214133. The reversal of 21214121 is 12141212.

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 21214121 - 2² = 21214117 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21214096 and 21214105.

It is not an unprimeable number, because it can be changed into a prime (21214111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31715 + ... + 32376.

It is an arithmetic number, because the mean of its divisors is an integer number (5319636).

Almost surely, 2^21214121 is an apocalyptic number.

It is an amenable number.

21214121 is a deficient number, since it is larger than the sum of its proper divisors (64423).

21214121 is an equidigital number, since it uses as much as digits as its factorization.

21214121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64422.

The product of its digits is 32, while the sum is 14.

The square root of 21214121 is about 4605.8789606328. The cubic root of 21214121 is about 276.8269368645.

Adding to 21214121 its reverse (12141212), we get a palindrome (33355333).

It can be divided in two parts, 2 and 1214121, that multiplied together give a palindrome (2428242).

The spelling of 21214121 in words is "twenty-one million, two hundred fourteen thousand, one hundred twenty-one".