20130813 has 12 divisors (see below), whose sum is σ = 29120988. Its totient is φ = 13400640.

The previous prime is 20130797. The next prime is 20130829. The reversal of 20130813 is 31803102.

It is an interprime number because it is at equal distance from previous prime (20130797) and next prime (20130829).

It can be written as a sum of positive squares in 2 ways, for example, as 10227204 + 9903609 = 3198^2 + 3147^2 .

It is not a de Polignac number, because 20130813 - 2⁴ = 20130797 is a prime.

It is a super-3 number, since 3×20130813³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20130833) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7281 + ... + 9657.

It is an arithmetic number, because the mean of its divisors is an integer number (2426749).

Almost surely, 2^20130813 is an apocalyptic number.

It is an amenable number.

20130813 is a deficient number, since it is larger than the sum of its proper divisors (8990175).

20130813 is a wasteful number, since it uses less digits than its factorization.

20130813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3324 (or 3321 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 20130813 is about 4486.7374561033. The cubic root of 20130813 is about 272.0322779241.

Adding to 20130813 its reverse (31803102), we get a palindrome (51933915).

The spelling of 20130813 in words is "twenty million, one hundred thirty thousand, eight hundred thirteen".