21041504 has 72 divisors (see below), whose sum is σ = 47659752. Its totient is φ = 9067520.

The previous prime is 21041479. The next prime is 21041513. The reversal of 21041504 is 40514012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 186152 + ... + 186264.

It is an arithmetic number, because the mean of its divisors is an integer number (661941).

Almost surely, 2^21041504 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 21041504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23829876).

21041504 is an abundant number, since it is smaller than the sum of its proper divisors (26618248).

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

21041504 is a wasteful number, since it uses less digits than its factorization.

21041504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21041504 is about 4587.1019173330. The cubic root of 21041504 is about 276.0740542026.

Adding to 21041504 its reverse (40514012), we get a palindrome (61555516).

It can be divided in two parts, 210 and 41504, that added together give a palindrome (41714).

The spelling of 21041504 in words is "twenty-one million, forty-one thousand, five hundred four".