21653065 has 16 divisors (see below), whose sum is σ = 31259520. Its totient is φ = 14065920.

The previous prime is 21653063. The next prime is 21653081. The reversal of 21653065 is 56035612.

It is not a de Polignac number, because 21653065 - 2¹ = 21653063 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21653063) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 15616 + ... + 16945.

It is an arithmetic number, because the mean of its divisors is an integer number (1953720).

Almost surely, 2^21653065 is an apocalyptic number.

It is an amenable number.

21653065 is a deficient number, since it is larger than the sum of its proper divisors (9606455).

21653065 is a wasteful number, since it uses less digits than its factorization.

21653065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32592.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 21653065 is about 4653.2853985115. The cubic root of 21653065 is about 278.7232045402.

Adding to 21653065 its reverse (56035612), we get a palindrome (77688677).

The spelling of 21653065 in words is "twenty-one million, six hundred fifty-three thousand, sixty-five".