21213004 has 12 divisors (see below), whose sum is σ = 37677304. Its totient is φ = 10448064.

The previous prime is 21212993. The next prime is 21213011. The reversal of 21213004 is 40031212.

It is a super-3 number, since 3×21213004³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 39309 + ... + 39844.

Almost surely, 2^21213004 is an apocalyptic number.

It is an amenable number.

21213004 is a deficient number, since it is larger than the sum of its proper divisors (16464300).

21213004 is a wasteful number, since it uses less digits than its factorization.

21213004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79224 (or 79222 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21213004 is about 4605.7577009652. The cubic root of 21213004 is about 276.8220781336.

Adding to 21213004 its reverse (40031212), we get a palindrome (61244216).

The spelling of 21213004 in words is "twenty-one million, two hundred thirteen thousand, four".