21092065 has 4 divisors (see below), whose sum is σ = 25310484. Its totient is φ = 16873648.

The previous prime is 21092063. The next prime is 21092089. The reversal of 21092065 is 56029012.

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 2782224 + 18309841 = 1668^2 + 4279^2 .

It is a cyclic number.

It is not a de Polignac number, because 21092065 - 2¹ = 21092063 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21092063) 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, 2109202 + ... + 2109211.

It is an arithmetic number, because the mean of its divisors is an integer number (6327621).

Almost surely, 2^21092065 is an apocalyptic number.

It is an amenable number.

21092065 is a deficient number, since it is larger than the sum of its proper divisors (4218419).

21092065 is an equidigital number, since it uses as much as digits as its factorization.

21092065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4218418.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21092065 is about 4592.6098244898. The cubic root of 21092065 is about 276.2950050548.

The spelling of 21092065 in words is "twenty-one million, ninety-two thousand, sixty-five".