20320513 has 4 divisors (see below), whose sum is σ = 20329540. Its totient is φ = 20311488.

The previous prime is 20320507. The next prime is 20320537. The reversal of 20320513 is 31502302.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4376464 + 15944049 = 2092^2 + 3993^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20320513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20320583) 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, 1933 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (5082385).

Almost surely, 2^20320513 is an apocalyptic number.

It is an amenable number.

20320513 is a deficient number, since it is larger than the sum of its proper divisors (9027).

20320513 is an equidigital number, since it uses as much as digits as its factorization.

20320513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9026.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 20320513 is about 4507.8279692109. The cubic root of 20320513 is about 272.8840943302.

Adding to 20320513 its reverse (31502302), we get a palindrome (51822815).

The spelling of 20320513 in words is "twenty million, three hundred twenty thousand, five hundred thirteen".