21417312 has 144 divisors (see below), whose sum is σ = 68085360. Its totient is φ = 5870592.

The previous prime is 21417307. The next prime is 21417317. The reversal of 21417312 is 21371412.

It is an interprime number because it is at equal distance from previous prime (21417307) and next prime (21417317).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21417317) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 136338 + ... + 136494.

It is an arithmetic number, because the mean of its divisors is an integer number (472815).

Almost surely, 2^21417312 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 21417312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34042680).

21417312 is an abundant number, since it is smaller than the sum of its proper divisors (46668048).

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

21417312 is a wasteful number, since it uses less digits than its factorization.

21417312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213 (or 198 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 21417312 is about 4627.8841817833. The cubic root of 21417312 is about 277.7079554761.

Adding to 21417312 its reverse (21371412), we get a palindrome (42788724).

It can be divided in two parts, 214173 and 12, that added together give a triangular number (214185 = T₆₅₄).

The spelling of 21417312 in words is "twenty-one million, four hundred seventeen thousand, three hundred twelve".