20001213 has 24 divisors (see below), whose sum is σ = 30115800. Its totient is φ = 12776064.

The previous prime is 20001203. The next prime is 20001217. The reversal of 20001213 is 31210002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6140484 + 13860729 = 2478^2 + 3723^2 .

It is not a de Polignac number, because 20001213 - 2⁵ = 20001181 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20001195 and 20001204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51223 + ... + 51611.

It is an arithmetic number, because the mean of its divisors is an integer number (1254825).

Almost surely, 2^20001213 is an apocalyptic number.

It is an amenable number.

20001213 is a deficient number, since it is larger than the sum of its proper divisors (10114587).

20001213 is a wasteful number, since it uses less digits than its factorization.

20001213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 621 (or 618 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 20001213 is about 4472.2715704662. The cubic root of 20001213 is about 271.4472491962.

Adding to 20001213 its reverse (31210002), we get a palindrome (51211215).

The spelling of 20001213 in words is "twenty million, one thousand, two hundred thirteen".