21837065 has 4 divisors (see below), whose sum is σ = 26204484. Its totient is φ = 17469648.

The previous prime is 21837059. The next prime is 21837073. The reversal of 21837065 is 56073812.

It is a happy number.

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 5345344 + 16491721 = 2312^2 + 4061^2 .

It is a cyclic number.

It is not a de Polignac number, because 21837065 - 2⁸ = 21836809 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 2183702 + ... + 2183711.

It is an arithmetic number, because the mean of its divisors is an integer number (6551121).

Almost surely, 2^21837065 is an apocalyptic number.

It is an amenable number.

21837065 is a deficient number, since it is larger than the sum of its proper divisors (4367419).

21837065 is an equidigital number, since it uses as much as digits as its factorization.

21837065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4367418.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21837065 is about 4673.0145516572. The cubic root of 21837065 is about 279.5104754443.

The spelling of 21837065 in words is "twenty-one million, eight hundred thirty-seven thousand, sixty-five".