21144234020 has 72 divisors (see below), whose sum is σ = 55625633784. Its totient is φ = 6691797504.

The previous prime is 21144234019. The next prime is 21144234031. The reversal of 21144234020 is 2043244112.

It can be written as a sum of positive squares in 4 ways, for example, as 4827748324 + 16316485696 = 69482^2 + 127736^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 817097 + ... + 842576.

It is an arithmetic number, because the mean of its divisors is an integer number (772578247).

Almost surely, 2^21144234020 is an apocalyptic number.

21144234020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144234020 is an abundant number, since it is smaller than the sum of its proper divisors (34481399764).

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

21144234020 is a wasteful number, since it uses less digits than its factorization.

21144234020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659709 (or 1659700 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21144234020 its reverse (2043244112), we get a palindrome (23187478132).

The spelling of 21144234020 in words is "twenty-one billion, one hundred forty-four million, two hundred thirty-four thousand, twenty".