21202261 has 2 divisors, whose sum is σ = 21202262. Its totient is φ = 21202260.

The previous prime is 21202211. The next prime is 21202273. The reversal of 21202261 is 16220212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12292036 + 8910225 = 3506^2 + 2985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202261 - 2⁷ = 21202133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21202201) 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, 10601130 + 10601131.

It is an arithmetic number, because the mean of its divisors is an integer number (10601131).

Almost surely, 2^21202261 is an apocalyptic number.

It is an amenable number.

21202261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202261 is an equidigital number, since it uses as much as digits as its factorization.

21202261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21202261 is about 4604.5912956526. The cubic root of 21202261 is about 276.7753394797.

Adding to 21202261 its reverse (16220212), we get a palindrome (37422473).

The spelling of 21202261 in words is "twenty-one million, two hundred two thousand, two hundred sixty-one".