21265441 has 2 divisors, whose sum is σ = 21265442. Its totient is φ = 21265440.

The previous prime is 21265399. The next prime is 21265459. The reversal of 21265441 is 14456212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16443025 + 4822416 = 4055^2 + 2196^2 .

It is a cyclic number.

It is not a de Polignac number, because 21265441 - 2¹⁷ = 21134369 is a prime.

It is not a weakly prime, because it can be changed into another prime (21265241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632720 + 10632721.

It is an arithmetic number, because the mean of its divisors is an integer number (10632721).

Almost surely, 2^21265441 is an apocalyptic number.

It is an amenable number.

21265441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21265441 is an equidigital number, since it uses as much as digits as its factorization.

21265441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 25.

The square root of 21265441 is about 4611.4467361122. The cubic root of 21265441 is about 277.0499851148.

The spelling of 21265441 in words is "twenty-one million, two hundred sixty-five thousand, four hundred forty-one".