21504413220 has 48 divisors (see below), whose sum is σ = 61232915520. Its totient is φ = 5637314176.

The previous prime is 21504413213. The next prime is 21504413243. The reversal of 21504413220 is 2231440512.

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 15 ways as a sum of consecutive naturals, for example, 3033807 + ... + 3040886.

It is an arithmetic number, because the mean of its divisors is an integer number (1275685740).

Almost surely, 2^21504413220 is an apocalyptic number.

21504413220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21504413220 is an abundant number, since it is smaller than the sum of its proper divisors (39728502300).

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

21504413220 is a wasteful number, since it uses less digits than its factorization.

21504413220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6074764 (or 6074762 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

Adding to 21504413220 its reverse (2231440512), we get a palindrome (23735853732).

The spelling of 21504413220 in words is "twenty-one billion, five hundred four million, four hundred thirteen thousand, two hundred twenty".