21213104 has 40 divisors (see below), whose sum is σ = 45895872. Its totient is φ = 9414720.

The previous prime is 21213097. The next prime is 21213109. The reversal of 21213104 is 40131212.

It is not an unprimeable number, because it can be changed into a prime (21213109) 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 7 ways as a sum of consecutive naturals, for example, 6167 + ... + 8969.

Almost surely, 2^21213104 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22947936).

21213104 is an abundant number, since it is smaller than the sum of its proper divisors (24682768).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21213104 is a wasteful number, since it uses less digits than its factorization.

21213104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2865 (or 2859 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21213104 is about 4605.7685569295. The cubic root of 21213104 is about 276.8225131209.

Adding to 21213104 its reverse (40131212), we get a palindrome (61344316).

It can be divided in two parts, 2121 and 3104, that added together give a palindrome (5225).

The spelling of 21213104 in words is "twenty-one million, two hundred thirteen thousand, one hundred four".