21756144331020 has 96 divisors (see below), whose sum is σ = 69344485378560. Its totient is φ = 5044903029760.

The previous prime is 21756144330881. The next prime is 21756144331027. The reversal of 21756144331020 is 2013344165712.

It is a self number, because there is not a number n which added to its sum of digits gives 21756144331020.

It is not an unprimeable number, because it can be changed into a prime (21756144331027) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 716590365 + ... + 716620724.

It is an arithmetic number, because the mean of its divisors is an integer number (722338389360).

Almost surely, 2^{21756144331020} is an apocalyptic number.

21756144331020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21756144331020 is an abundant number, since it is smaller than the sum of its proper divisors (47588341047540).

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

21756144331020 is a wasteful number, since it uses less digits than its factorization.

21756144331020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1433211135 (or 1433211133 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 39.

Adding to 21756144331020 its reverse (2013344165712), we get a palindrome (23769488496732).

The spelling of 21756144331020 in words is "twenty-one trillion, seven hundred fifty-six billion, one hundred forty-four million, three hundred thirty-one thousand, twenty".