21215324 has 48 divisors (see below), whose sum is σ = 42688800. Its totient is φ = 9144576.

The previous prime is 21215323. The next prime is 21215329. The reversal of 21215324 is 42351212.

It is a junction number, because it is equal to n+sod(n) for n = 21215296 and 21215305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107594 + ... + 107790.

It is an arithmetic number, because the mean of its divisors is an integer number (889350).

Almost surely, 2^21215324 is an apocalyptic number.

It is an amenable number.

21215324 is an abundant number, since it is smaller than the sum of its proper divisors (21473476).

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

21215324 is a wasteful number, since it uses less digits than its factorization.

21215324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 340 counting only the distinct ones).

The product of its digits is 480, while the sum is 20.

The square root of 21215324 is about 4606.0095527474. The cubic root of 21215324 is about 276.8321694878.

Adding to 21215324 its reverse (42351212), we get a palindrome (63566536).

The spelling of 21215324 in words is "twenty-one million, two hundred fifteen thousand, three hundred twenty-four".