20643065 has 4 divisors (see below), whose sum is σ = 24771684. Its totient is φ = 16514448.

The previous prime is 20643061. The next prime is 20643107. The reversal of 20643065 is 56034602.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11377129 + 9265936 = 3373^2 + 3044^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643065 - 2² = 20643061 is a prime.

It is a super-2 number, since 2×20643065² = 852272265188450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20643061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2064302 + ... + 2064311.

It is an arithmetic number, because the mean of its divisors is an integer number (6192921).

Almost surely, 2^20643065 is an apocalyptic number.

It is an amenable number.

20643065 is a deficient number, since it is larger than the sum of its proper divisors (4128619).

20643065 is an equidigital number, since it uses as much as digits as its factorization.

20643065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4128618.

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 20643065 is about 4543.4639868717. The cubic root of 20643065 is about 274.3203713519.

Adding to 20643065 its reverse (56034602), we get a palindrome (76677667).

The spelling of 20643065 in words is "twenty million, six hundred forty-three thousand, sixty-five".