20345665 has 16 divisors (see below), whose sum is σ = 25172928. Its totient is φ = 15777216.

The previous prime is 20345659. The next prime is 20345669. The reversal of 20345665 is 56654302.

It is a de Polignac number, because none of the positive numbers 2^k-20345665 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20345669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36922 + ... + 37468.

It is an arithmetic number, because the mean of its divisors is an integer number (1573308).

Almost surely, 2^20345665 is an apocalyptic number.

It is an amenable number.

20345665 is a deficient number, since it is larger than the sum of its proper divisors (4827263).

20345665 is a wasteful number, since it uses less digits than its factorization.

20345665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 20345665 is about 4510.6169201119. The cubic root of 20345665 is about 272.9966366145.

Adding to 20345665 its reverse (56654302), we get a palindrome (76999967).

The spelling of 20345665 in words is "twenty million, three hundred forty-five thousand, six hundred sixty-five".