20002813 has 4 divisors (see below), whose sum is σ = 20016828. Its totient is φ = 19988800.

The previous prime is 20002799. The next prime is 20002823. The reversal of 20002813 is 31820002.

20002813 = 3162² + 3163².

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31820002 = 2 ⋅15910001.

It can be written as a sum of positive squares in 2 ways, for example, as 10004569 + 9998244 = 3163^2 + 3162^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20002813 is a prime.

It is a super-2 number, since 2×20002813² = 800225055825938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20002823) 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, 4588 + ... + 7813.

It is an arithmetic number, because the mean of its divisors is an integer number (5004207).

Almost surely, 2^20002813 is an apocalyptic number.

20002813 is the 3163-rd centered square number.

It is an amenable number.

20002813 is a deficient number, since it is larger than the sum of its proper divisors (14015).

20002813 is a wasteful number, since it uses less digits than its factorization.

20002813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14014.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 20002813 is about 4472.4504469027. The cubic root of 20002813 is about 271.4544871575.

Adding to 20002813 its reverse (31820002), we get a palindrome (51822815).

The spelling of 20002813 in words is "twenty million, two thousand, eight hundred thirteen".