21255354123143 has 48 divisors (see below), whose sum is σ = 26229975704064. Its totient is φ = 17137999327680.

The previous prime is 21255354123131. The next prime is 21255354123161. The reversal of 21255354123143 is 34132145355212.

It is a de Polignac number, because none of the positive numbers 2^k-21255354123143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21255354123143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255354123193) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 31432196 + ... + 32101302.

It is an arithmetic number, because the mean of its divisors is an integer number (546457827168).

Almost surely, 2^{21255354123143} is an apocalyptic number.

21255354123143 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21255354123143 is a deficient number, since it is larger than the sum of its proper divisors (4974621580921).

21255354123143 is a wasteful number, since it uses less digits than its factorization.

21255354123143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669612 (or 669605 counting only the distinct ones).

The product of its digits is 432000, while the sum is 41.

Adding to 21255354123143 its reverse (34132145355212), we get a palindrome (55387499478355).

The spelling of 21255354123143 in words is "twenty-one trillion, two hundred fifty-five billion, three hundred fifty-four million, one hundred twenty-three thousand, one hundred forty-three".