21222401 has 2 divisors, whose sum is σ = 21222402. Its totient is φ = 21222400.

The previous prime is 21222391. The next prime is 21222433. The reversal of 21222401 is 10422212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18054001 + 3168400 = 4249^2 + 1780^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222401 - 2¹⁰ = 21221377 is a prime.

It is a Chen prime.

It is equal to p_1343102 and since 21222401 and 1343102 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21252401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611200 + 10611201.

It is an arithmetic number, because the mean of its divisors is an integer number (10611201).

Almost surely, 2^21222401 is an apocalyptic number.

It is an amenable number.

21222401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222401 is an equidigital number, since it uses as much as digits as its factorization.

21222401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21222401 is about 4606.7777241799. Note that the first 4 decimals coincide. The cubic root of 21222401 is about 276.8629479235.

Adding to 21222401 its reverse (10422212), we get a palindrome (31644613).

The spelling of 21222401 in words is "twenty-one million, two hundred twenty-two thousand, four hundred one".