21540145251143 has 4 divisors (see below), whose sum is σ = 21563789758368. Its totient is φ = 21516500743920.

The previous prime is 21540145251133. The next prime is 21540145251167. The reversal of 21540145251143 is 34115254104512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21540145251143 - 2³⁴ = 21522965381959 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21540145251097 and 21540145251106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540145251133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11822252246 + ... + 11822254067.

It is an arithmetic number, because the mean of its divisors is an integer number (5390947439592).

Almost surely, 2^{21540145251143} is an apocalyptic number.

21540145251143 is a deficient number, since it is larger than the sum of its proper divisors (23644507225).

21540145251143 is an equidigital number, since it uses as much as digits as its factorization.

21540145251143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23644507224.

The product of its (nonzero) digits is 96000, while the sum is 38.

Adding to 21540145251143 its reverse (34115254104512), we get a palindrome (55655399355655).

The spelling of 21540145251143 in words is "twenty-one trillion, five hundred forty billion, one hundred forty-five million, two hundred fifty-one thousand, one hundred forty-three".