21004124 has 12 divisors (see below), whose sum is σ = 37612344. Its totient is φ = 10257744.

The previous prime is 21004117. The next prime is 21004153. The reversal of 21004124 is 42140012.

It is a junction number, because it is equal to n+sod(n) for n = 21004099 and 21004108.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60887 + ... + 61230.

It is an arithmetic number, because the mean of its divisors is an integer number (3134362).

Almost surely, 2^21004124 is an apocalyptic number.

It is an amenable number.

21004124 is a deficient number, since it is larger than the sum of its proper divisors (16608220).

21004124 is a wasteful number, since it uses less digits than its factorization.

21004124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122164 (or 122162 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21004124 is about 4583.0256381565. The cubic root of 21004124 is about 275.9104764613.

Adding to 21004124 its reverse (42140012), we get a palindrome (63144136).

The spelling of 21004124 in words is "twenty-one million, four thousand, one hundred twenty-four".