21331201 has 2 divisors, whose sum is σ = 21331202. Its totient is φ = 21331200.

The previous prime is 21331187. The next prime is 21331217. The reversal of 21331201 is 10213312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19793601 + 1537600 = 4449^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 21331201 - 2¹⁷ = 21200129 is a prime.

It is a super-2 number, since 2×21331201² = 910040272204802, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21331001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665600 + 10665601.

It is an arithmetic number, because the mean of its divisors is an integer number (10665601).

Almost surely, 2^21331201 is an apocalyptic number.

It is an amenable number.

21331201 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331201 is an equidigital number, since it uses as much as digits as its factorization.

21331201 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21331201 is about 4618.5713158941. The cubic root of 21331201 is about 277.3352689489.

Adding to 21331201 its reverse (10213312), we get a palindrome (31544513).

The spelling of 21331201 in words is "twenty-one million, three hundred thirty-one thousand, two hundred one".