21170212 has 48 divisors (see below), whose sum is σ = 44900352. Its totient is φ = 8537760.

The previous prime is 21170209. The next prime is 21170213. The reversal of 21170212 is 21207112.

It is a super-2 number, since 2×21170212² = 896355752249888, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21170213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45493 + ... + 45955.

It is an arithmetic number, because the mean of its divisors is an integer number (935424).

Almost surely, 2^21170212 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 21170212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22450176).

21170212 is an abundant number, since it is smaller than the sum of its proper divisors (23730140).

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

21170212 is a wasteful number, since it uses less digits than its factorization.

21170212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568 (or 566 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21170212 is about 4601.1098661084. The cubic root of 21170212 is about 276.6358127558.

Adding to 21170212 its reverse (21207112), we get a palindrome (42377324).

The spelling of 21170212 in words is "twenty-one million, one hundred seventy thousand, two hundred twelve".