21603065 has 16 divisors (see below), whose sum is σ = 28817856. Its totient is φ = 15412800.

The previous prime is 21603053. The next prime is 21603077. The reversal of 21603065 is 56030612.

It is an interprime number because it is at equal distance from previous prime (21603053) and next prime (21603077).

It is not a de Polignac number, because 21603065 - 2¹⁰ = 21602041 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21603065.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 791 + ... + 6620.

It is an arithmetic number, because the mean of its divisors is an integer number (1801116).

Almost surely, 2^21603065 is an apocalyptic number.

It is an amenable number.

21603065 is a deficient number, since it is larger than the sum of its proper divisors (7214791).

21603065 is a wasteful number, since it uses less digits than its factorization.

21603065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7480.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 21603065 is about 4647.9097452511. The cubic root of 21603065 is about 278.5085020510.

Adding to 21603065 its reverse (56030612), we get a palindrome (77633677).

It can be divided in two parts, 2160 and 3065, that added together give a palindrome (5225).

The spelling of 21603065 in words is "twenty-one million, six hundred three thousand, sixty-five".