20663365 has 4 divisors (see below), whose sum is σ = 24796044. Its totient is φ = 16530688.

The previous prime is 20663359. The next prime is 20663371. The reversal of 20663365 is 56336602.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20663359) and next prime (20663371).

It can be written as a sum of positive squares in 2 ways, for example, as 3207681 + 17455684 = 1791^2 + 4178^2 .

It is a cyclic number.

It is not a de Polignac number, because 20663365 - 2⁵ = 20663333 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2066332 + ... + 2066341.

It is an arithmetic number, because the mean of its divisors is an integer number (6199011).

Almost surely, 2^20663365 is an apocalyptic number.

It is an amenable number.

20663365 is a deficient number, since it is larger than the sum of its proper divisors (4132679).

20663365 is an equidigital number, since it uses as much as digits as its factorization.

20663365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4132678.

The product of its (nonzero) digits is 19440, while the sum is 31.

The square root of 20663365 is about 4545.6974162388. The cubic root of 20663365 is about 274.4102623823.

Adding to 20663365 its reverse (56336602), we get a palindrome (76999967).

The spelling of 20663365 in words is "twenty million, six hundred sixty-three thousand, three hundred sixty-five".