21240235255133 has 4 divisors (see below), whose sum is σ = 21588435833148. Its totient is φ = 20892034677120.

The previous prime is 21240235255123. The next prime is 21240235255177. The reversal of 21240235255133 is 33155253204212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1667512507684 + 19572722747449 = 1291322^2 + 4424107^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240235255133 - 2¹⁴ = 21240235238749 is a prime.

It is a super-2 number, since 2×21240235255133² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240235255123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174100288916 + ... + 174100289037.

It is an arithmetic number, because the mean of its divisors is an integer number (5397108958287).

Almost surely, 2^{21240235255133} is an apocalyptic number.

It is an amenable number.

21240235255133 is a deficient number, since it is larger than the sum of its proper divisors (348200578015).

21240235255133 is an equidigital number, since it uses as much as digits as its factorization.

21240235255133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348200578014.

The product of its (nonzero) digits is 216000, while the sum is 38.

Adding to 21240235255133 its reverse (33155253204212), we get a palindrome (54395488459345).

The spelling of 21240235255133 in words is "twenty-one trillion, two hundred forty billion, two hundred thirty-five million, two hundred fifty-five thousand, one hundred thirty-three".