21124624 has 20 divisors (see below), whose sum is σ = 41208300. Its totient is φ = 10490240.

The previous prime is 21124619. The next prime is 21124627. The reversal of 21124624 is 42642112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 13104400 + 8020224 = 3620^2 + 2832^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21124595 and 21124604.

It is not an unprimeable number, because it can be changed into a prime (21124627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2047 + ... + 6814.

It is an arithmetic number, because the mean of its divisors is an integer number (2060415).

Almost surely, 2^21124624 is an apocalyptic number.

It is an amenable number.

21124624 is a deficient number, since it is larger than the sum of its proper divisors (20083676).

21124624 is a wasteful number, since it uses less digits than its factorization.

21124624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9018 (or 9012 counting only the distinct ones).

The product of its digits is 768, while the sum is 22.

The square root of 21124624 is about 4596.1531741229. The cubic root of 21124624 is about 276.4371005801.

Adding to 21124624 its reverse (42642112), we get a palindrome (63766736).

The spelling of 21124624 in words is "twenty-one million, one hundred twenty-four thousand, six hundred twenty-four".