21130065 has 112 divisors (see below), whose sum is σ = 45328896. Its totient is φ = 9331200.

The previous prime is 21130049. The next prime is 21130073. The reversal of 21130065 is 56003112.

It is not a de Polignac number, because 21130065 - 2⁴ = 21130049 is a prime.

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 111 ways as a sum of consecutive naturals, for example, 681600 + ... + 681630.

Almost surely, 2^21130065 is an apocalyptic number.

It is an amenable number.

21130065 is an abundant number, since it is smaller than the sum of its proper divisors (24198831).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21130065 is a wasteful number, since it uses less digits than its factorization.

21130065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 21130065 is about 4596.7450440502. The cubic root of 21130065 is about 276.4608322080.

Adding to 21130065 its reverse (56003112), we get a palindrome (77133177).

It can be divided in two parts, 211 and 30065, that added together give a square (30276 = 174²).

The spelling of 21130065 in words is "twenty-one million, one hundred thirty thousand, sixty-five".