20613311 has 4 divisors (see below), whose sum is σ = 20736912. Its totient is φ = 20489712.

The previous prime is 20613301. The next prime is 20613323. The reversal of 20613311 is 11331602.

20613311 is nontrivially palindromic in base 13.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20613311 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20613311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20613301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61550 + ... + 61883.

It is an arithmetic number, because the mean of its divisors is an integer number (5184228).

Almost surely, 2^20613311 is an apocalyptic number.

20613311 is a deficient number, since it is larger than the sum of its proper divisors (123601).

20613311 is a wasteful number, since it uses less digits than its factorization.

20613311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123600.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 20613311 is about 4540.1884322129. The cubic root of 20613311 is about 274.1885102324.

Adding to 20613311 its reverse (11331602), we get a palindrome (31944913).

The spelling of 20613311 in words is "twenty million, six hundred thirteen thousand, three hundred eleven".