21163504 has 40 divisors (see below), whose sum is σ = 44930160. Its totient is φ = 9612288.

The previous prime is 21163481. The next prime is 21163507. The reversal of 21163504 is 40536112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21163507) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 6547 + ... + 9229.

It is an arithmetic number, because the mean of its divisors is an integer number (1123254).

Almost surely, 2^21163504 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 21163504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22465080).

21163504 is an abundant number, since it is smaller than the sum of its proper divisors (23766656).

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

21163504 is a wasteful number, since it uses less digits than its factorization.

21163504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2737 (or 2731 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21163504 is about 4600.3808537990. The cubic root of 21163504 is about 276.6065913658.

Adding to 21163504 its reverse (40536112), we get a palindrome (61699616).

The spelling of 21163504 in words is "twenty-one million, one hundred sixty-three thousand, five hundred four".