21438843516831 has 32 divisors (see below), whose sum is σ = 30921249300480. Its totient is φ = 13134335203584.

The previous prime is 21438843516793. The next prime is 21438843516859. The reversal of 21438843516831 is 13861534883412.

It is a happy number.

It is not a de Polignac number, because 21438843516831 - 2¹⁹ = 21438842992543 is a prime.

It is a super-2 number, since 2×21438843516831² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21438843516131) 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, 33922930 + ... + 34549136.

It is an arithmetic number, because the mean of its divisors is an integer number (966289040640).

Almost surely, 2^{21438843516831} is an apocalyptic number.

21438843516831 is a deficient number, since it is larger than the sum of its proper divisors (9482405783649).

21438843516831 is a wasteful number, since it uses less digits than its factorization.

21438843516831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630135.

The product of its digits is 13271040, while the sum is 57.

The spelling of 21438843516831 in words is "twenty-one trillion, four hundred thirty-eight billion, eight hundred forty-three million, five hundred sixteen thousand, eight hundred thirty-one".