21241312 has 36 divisors (see below), whose sum is σ = 42933240. Its totient is φ = 10344768.

The previous prime is 21241271. The next prime is 21241327. The reversal of 21241312 is 21314212.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 58989 + ... + 59347.

It is an arithmetic number, because the mean of its divisors is an integer number (1192590).

Almost surely, 2^21241312 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 21241312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21466620).

21241312 is an abundant number, since it is smaller than the sum of its proper divisors (21691928).

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

21241312 is an equidigital number, since it uses as much as digits as its factorization.

21241312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455 (or 404 counting only the distinct ones).

The product of its digits is 96, while the sum is 16.

The square root of 21241312 is about 4608.8297863991. The cubic root of 21241312 is about 276.9451598091.

Adding to 21241312 its reverse (21314212), we get a palindrome (42555524).

Subtracting 21241312 from its reverse (21314212), we obtain a square (72900 = 270²).

The spelling of 21241312 in words is "twenty-one million, two hundred forty-one thousand, three hundred twelve".