21041365 has 4 divisors (see below), whose sum is σ = 25249644. Its totient is φ = 16833088.

The previous prime is 21041357. The next prime is 21041369. The reversal of 21041365 is 56314012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3392964 + 17648401 = 1842^2 + 4201^2 .

It is a cyclic number.

It is not a de Polignac number, because 21041365 - 2³ = 21041357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21041369) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2104132 + ... + 2104141.

It is an arithmetic number, because the mean of its divisors is an integer number (6312411).

Almost surely, 2^21041365 is an apocalyptic number.

It is an amenable number.

21041365 is a deficient number, since it is larger than the sum of its proper divisors (4208279).

21041365 is an equidigital number, since it uses as much as digits as its factorization.

21041365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208278.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21041365 is about 4587.0867661295. The cubic root of 21041365 is about 276.0734462870.

Adding to 21041365 its reverse (56314012), we get a palindrome (77355377).

The spelling of 21041365 in words is "twenty-one million, forty-one thousand, three hundred sixty-five".