21214021 has 2 divisors, whose sum is σ = 21214022. Its totient is φ = 21214020.

The previous prime is 21214003. The next prime is 21214049. The reversal of 21214021 is 12041212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20349121 + 864900 = 4511^2 + 930^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214021 - 2⁷ = 21213893 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21213992 and 21214010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21214001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607010 + 10607011.

It is an arithmetic number, because the mean of its divisors is an integer number (10607011).

Almost surely, 2^21214021 is an apocalyptic number.

It is an amenable number.

21214021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21214021 is an equidigital number, since it uses as much as digits as its factorization.

21214021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 21214021 is about 4605.8681049288. The cubic root of 21214021 is about 276.8265018911.

Adding to 21214021 its reverse (12041212), we get a palindrome (33255233).

The spelling of 21214021 in words is "twenty-one million, two hundred fourteen thousand, twenty-one".