21020244143440 has 20 divisors (see below), whose sum is σ = 48872067633684. Its totient is φ = 8408097657344.

The previous prime is 21020244143323. The next prime is 21020244143441. The reversal of 21020244143440 is 4434144202012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14543605977664 + 6476638165776 = 3813608^2 + 2544924^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020244143441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131376525817 + ... + 131376525976.

Almost surely, 2^{21020244143440} is an apocalyptic number.

21020244143440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020244143440 is an abundant number, since it is smaller than the sum of its proper divisors (27851823490244).

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

21020244143440 is a wasteful number, since it uses less digits than its factorization.

21020244143440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262753051806 (or 262753051800 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 31.

Adding to 21020244143440 its reverse (4434144202012), we get a palindrome (25454388345452).

The spelling of 21020244143440 in words is "twenty-one trillion, twenty billion, two hundred forty-four million, one hundred forty-three thousand, four hundred forty".