21052065 has 16 divisors (see below), whose sum is σ = 34505856. Its totient is φ = 10953600.

The previous prime is 21052063. The next prime is 21052079. The reversal of 21052065 is 56025012.

It is not a de Polignac number, because 21052065 - 2¹ = 21052063 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21052063) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16501 + ... + 17730.

It is an arithmetic number, because the mean of its divisors is an integer number (2156616).

Almost surely, 2^21052065 is an apocalyptic number.

It is an amenable number.

21052065 is a deficient number, since it is larger than the sum of its proper divisors (13453791).

21052065 is a wasteful number, since it uses less digits than its factorization.

21052065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34280.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21052065 is about 4588.2529354864. The cubic root of 21052065 is about 276.1202348436.

Adding to 21052065 its reverse (56025012), we get a palindrome (77077077).

The spelling of 21052065 in words is "twenty-one million, fifty-two thousand, sixty-five".