21520116585143 has 12 divisors (see below), whose sum is σ = 23746383302880. Its totient is φ = 19487618810880.

The previous prime is 21520116585131. The next prime is 21520116585193. The reversal of 21520116585143 is 34158561102512.

It is not a de Polignac number, because 21520116585143 - 2¹⁶ = 21520116519607 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21520116585094 and 21520116585103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520116585193) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 345984863 + ... + 346047056.

It is an arithmetic number, because the mean of its divisors is an integer number (1978865275240).

Almost surely, 2^{21520116585143} is an apocalyptic number.

21520116585143 is a deficient number, since it is larger than the sum of its proper divisors (2226266717737).

21520116585143 is a wasteful number, since it uses less digits than its factorization.

21520116585143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692032198 (or 692032187 counting only the distinct ones).

The product of its (nonzero) digits is 288000, while the sum is 44.

Adding to 21520116585143 its reverse (34158561102512), we get a palindrome (55678677687655).

The spelling of 21520116585143 in words is "twenty-one trillion, five hundred twenty billion, one hundred sixteen million, five hundred eighty-five thousand, one hundred forty-three".