21663205054361 has 8 divisors (see below), whose sum is σ = 23431481452680. Its totient is φ = 19909482371712.

The previous prime is 21663205054327. The next prime is 21663205054399. The reversal of 21663205054361 is 16345050236612.

It can be written as a sum of positive squares in 4 ways, for example, as 1945520042761 + 19717685011600 = 1394819^2 + 4440460^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21663205054361 - 2¹⁰ = 21663205053337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21663205054661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3638425820 + ... + 3638431773.

It is an arithmetic number, because the mean of its divisors is an integer number (2928935181585).

Almost surely, 2^{21663205054361} is an apocalyptic number.

It is an amenable number.

21663205054361 is a deficient number, since it is larger than the sum of its proper divisors (1768276398319).

21663205054361 is a wasteful number, since it uses less digits than its factorization.

21663205054361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7276857835.

The product of its (nonzero) digits is 777600, while the sum is 44.

The spelling of 21663205054361 in words is "twenty-one trillion, six hundred sixty-three billion, two hundred five million, fifty-four thousand, three hundred sixty-one".