21003124 has 24 divisors (see below), whose sum is σ = 37997568. Its totient is φ = 10150560.

The previous prime is 21003121. The next prime is 21003139. The reversal of 21003124 is 42130012.

It is a super-2 number, since 2×21003124² = 882262435518752, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27897 + ... + 28639.

It is an arithmetic number, because the mean of its divisors is an integer number (1583232).

Almost surely, 2^21003124 is an apocalyptic number.

It is an amenable number.

21003124 is a deficient number, since it is larger than the sum of its proper divisors (16994444).

21003124 is a wasteful number, since it uses less digits than its factorization.

21003124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 975 (or 973 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21003124 is about 4582.9165386247. The cubic root of 21003124 is about 275.9060977203.

Adding to 21003124 its reverse (42130012), we get a palindrome (63133136).

The spelling of 21003124 in words is "twenty-one million, three thousand, one hundred twenty-four".