21330210 has 64 divisors (see below), whose sum is σ = 56453760. Its totient is φ = 5114880.

The previous prime is 21330163. The next prime is 21330251. The reversal of 21330210 is 1203312.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35674 + ... + 36266.

It is an arithmetic number, because the mean of its divisors is an integer number (882090).

Almost surely, 2^21330210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21330210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28226880).

21330210 is an abundant number, since it is smaller than the sum of its proper divisors (35123550).

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

21330210 is a wasteful number, since it uses less digits than its factorization.

21330210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723.

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

The square root of 21330210 is about 4618.4640303893. The cubic root of 21330210 is about 277.3309740898.

Adding to 21330210 its product of nonzero digits (36), we get a triangular number (21330246 = T₆₅₃₁).

Adding to 21330210 its reverse (1203312), we get a palindrome (22533522).

It can be divided in two parts, 213302 and 10, that added together give a palindrome (213312).

The spelling of 21330210 in words is "twenty-one million, three hundred thirty thousand, two hundred ten".