21213003 has 8 divisors (see below), whose sum is σ = 32324608. Its totient is φ = 12121704.

The previous prime is 21212993. The next prime is 21213011. The reversal of 21213003 is 30031212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21213003 - 2⁹ = 21212491 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21213003.

It is not an unprimeable number, because it can be changed into a prime (21213013) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 505051 + ... + 505092.

It is an arithmetic number, because the mean of its divisors is an integer number (4040576).

Almost surely, 2^21213003 is an apocalyptic number.

21213003 is a deficient number, since it is larger than the sum of its proper divisors (11111605).

21213003 is a wasteful number, since it uses less digits than its factorization.

21213003 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010153.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21213003 is about 4605.7575924054. The cubic root of 21213003 is about 276.8220737837.

Adding to 21213003 its reverse (30031212), we get a palindrome (51244215).

The spelling of 21213003 in words is "twenty-one million, two hundred thirteen thousand, three".