21663406441101 has 4 divisors (see below), whose sum is σ = 28884541921472. Its totient is φ = 14442270960732.

The previous prime is 21663406441069. The next prime is 21663406441129. The reversal of 21663406441101 is 10114460436612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21663406441101 - 2⁵ = 21663406441069 is a prime.

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 21663406441101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21663406441151) 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, 3610567740181 + ... + 3610567740186.

It is an arithmetic number, because the mean of its divisors is an integer number (7221135480368).

Almost surely, 2^{21663406441101} is an apocalyptic number.

It is an amenable number.

21663406441101 is a deficient number, since it is larger than the sum of its proper divisors (7221135480371).

21663406441101 is an equidigital number, since it uses as much as digits as its factorization.

21663406441101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7221135480370.

The product of its (nonzero) digits is 82944, while the sum is 39.

Adding to 21663406441101 its reverse (10114460436612), we get a palindrome (31777866877713).

The spelling of 21663406441101 in words is "twenty-one trillion, six hundred sixty-three billion, four hundred six million, four hundred forty-one thousand, one hundred one".