21265253 has 2 divisors, whose sum is σ = 21265254. Its totient is φ = 21265252.

The previous prime is 21265241. The next prime is 21265259. The reversal of 21265253 is 35256212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21224449 + 40804 = 4607^2 + 202^2 .

It is a cyclic number.

It is not a de Polignac number, because 21265253 - 2²⁴ = 4488037 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21265259) 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, 10632626 + 10632627.

It is an arithmetic number, because the mean of its divisors is an integer number (10632627).

Almost surely, 2^21265253 is an apocalyptic number.

It is an amenable number.

21265253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21265253 is an equidigital number, since it uses as much as digits as its factorization.

21265253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 26.

The square root of 21265253 is about 4611.4263520087. The cubic root of 21265253 is about 277.0491686798.

The spelling of 21265253 in words is "twenty-one million, two hundred sixty-five thousand, two hundred fifty-three".