21255361 has 2 divisors, whose sum is σ = 21255362. Its totient is φ = 21255360.

The previous prime is 21255329. The next prime is 21255383. The reversal of 21255361 is 16355212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11861136 + 9394225 = 3444^2 + 3065^2 .

It is a cyclic number.

It is not a de Polignac number, because 21255361 - 2⁵ = 21255329 is a prime.

It is not a weakly prime, because it can be changed into another prime (21255301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627680 + 10627681.

It is an arithmetic number, because the mean of its divisors is an integer number (10627681).

Almost surely, 2^21255361 is an apocalyptic number.

It is an amenable number.

21255361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255361 is an equidigital number, since it uses as much as digits as its factorization.

21255361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 25.

The square root of 21255361 is about 4610.3536740688. The cubic root of 21255361 is about 277.0062035129.

The spelling of 21255361 in words is "twenty-one million, two hundred fifty-five thousand, three hundred sixty-one".