21466021 has 2 divisors, whose sum is σ = 21466022. Its totient is φ = 21466020.

The previous prime is 21465979. The next prime is 21466037. The reversal of 21466021 is 12066412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17969121 + 3496900 = 4239^2 + 1870^2 .

It is a cyclic number.

It is not a de Polignac number, because 21466021 - 2¹³ = 21457829 is a prime.

It is a Chen prime.

It is equal to p_1357600 and since 21466021 and 1357600 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21465983 and 21466001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21466091) 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 as a sum of consecutive naturals, namely, 10733010 + 10733011.

It is an arithmetic number, because the mean of its divisors is an integer number (10733011).

Almost surely, 2^21466021 is an apocalyptic number.

It is an amenable number.

21466021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21466021 is an equidigital number, since it uses as much as digits as its factorization.

21466021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21466021 is about 4633.1437491190. The cubic root of 21466021 is about 277.9183247807.

The spelling of 21466021 in words is "twenty-one million, four hundred sixty-six thousand, twenty-one".