21520535321167 has 2 divisors, whose sum is σ = 21520535321168. Its totient is φ = 21520535321166.

The previous prime is 21520535321071. The next prime is 21520535321179. The reversal of 21520535321167 is 76112353502512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21520535321167 - 2¹¹ = 21520535319119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21520535331167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760267660583 + 10760267660584.

It is an arithmetic number, because the mean of its divisors is an integer number (10760267660584).

Almost surely, 2^{21520535321167} is an apocalyptic number.

21520535321167 is a deficient number, since it is larger than the sum of its proper divisors (1).

21520535321167 is an equidigital number, since it uses as much as digits as its factorization.

21520535321167 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378000, while the sum is 43.

Adding to 21520535321167 its reverse (76112353502512), we get a palindrome (97632888823679).

The spelling of 21520535321167 in words is "twenty-one trillion, five hundred twenty billion, five hundred thirty-five million, three hundred twenty-one thousand, one hundred sixty-seven".