21601223355263 has 4 divisors (see below), whose sum is σ = 21766118190168. Its totient is φ = 21436328520360.

The previous prime is 21601223355253. The next prime is 21601223355269. The reversal of 21601223355263 is 36255332210612.

It is a happy number.

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 21601223355263 - 2¹² = 21601223351167 is a prime.

It is a super-2 number, since 2×21601223355263² (a number of 27 digits) contains 22 as substring.

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 21601223355263.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601223355269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82447417256 + ... + 82447417517.

It is an arithmetic number, because the mean of its divisors is an integer number (5441529547542).

Almost surely, 2^{21601223355263} is an apocalyptic number.

21601223355263 is a deficient number, since it is larger than the sum of its proper divisors (164894834905).

21601223355263 is a wasteful number, since it uses less digits than its factorization.

21601223355263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164894834904.

The product of its (nonzero) digits is 388800, while the sum is 41.

Adding to 21601223355263 its reverse (36255332210612), we get a palindrome (57856555565875).

The spelling of 21601223355263 in words is "twenty-one trillion, six hundred one billion, two hundred twenty-three million, three hundred fifty-five thousand, two hundred sixty-three".