21601550065117 has 4 divisors (see below), whose sum is σ = 23565327343776. Its totient is φ = 19637772786460.

The previous prime is 21601550065093. The next prime is 21601550065159. The reversal of 21601550065117 is 71156005510612.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21601550065117 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 21601550065117.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601550065517) 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, 981888639313 + ... + 981888639334.

It is an arithmetic number, because the mean of its divisors is an integer number (5891331835944).

Almost surely, 2^{21601550065117} is an apocalyptic number.

It is an amenable number.

21601550065117 is a deficient number, since it is larger than the sum of its proper divisors (1963777278659).

21601550065117 is a wasteful number, since it uses less digits than its factorization.

21601550065117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1963777278658.

The product of its (nonzero) digits is 63000, while the sum is 40.

Adding to 21601550065117 its reverse (71156005510612), we get a palindrome (92757555575729).

The spelling of 21601550065117 in words is "twenty-one trillion, six hundred one billion, five hundred fifty million, sixty-five thousand, one hundred seventeen".