21504112020 has 72 divisors (see below), whose sum is σ = 65255711976. Its totient is φ = 5732093952.

The previous prime is 21504111989. The next prime is 21504112031. The reversal of 21504112020 is 2021140512.

21504112020 is a `hidden beast` number, since 2 + 1 + 50 + 411 + 202 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5258570256 + 16245541764 = 72516^2 + 127458^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21504111984 and 21504112002.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 443704 + ... + 489776.

It is an arithmetic number, because the mean of its divisors is an integer number (906329333).

Almost surely, 2^21504112020 is an apocalyptic number.

21504112020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21504112020 is an abundant number, since it is smaller than the sum of its proper divisors (43751599956).

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

21504112020 is a wasteful number, since it uses less digits than its factorization.

21504112020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48681 (or 48676 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21504112020 its reverse (2021140512), we get a palindrome (23525252532).

The spelling of 21504112020 in words is "twenty-one billion, five hundred four million, one hundred twelve thousand, twenty".