21201201423205 has 8 divisors (see below), whose sum is σ = 26318732801400. Its totient is φ = 16376100409536.

The previous prime is 21201201423203. The next prime is 21201201423223. The reversal of 21201201423205 is 50232410210212.

It can be written as a sum of positive squares in 4 ways, for example, as 16151613921 + 21185049809284 = 127089^2 + 4602722^2 .

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 21201201423205 - 2¹ = 21201201423203 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21201201423205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201201423203) 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, 73107590970 + ... + 73107591259.

It is an arithmetic number, because the mean of its divisors is an integer number (3289841600175).

Almost surely, 2^{21201201423205} is an apocalyptic number.

It is an amenable number.

21201201423205 is a deficient number, since it is larger than the sum of its proper divisors (5117531378195).

21201201423205 is a wasteful number, since it uses less digits than its factorization.

21201201423205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146215182263.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21201201423205 its reverse (50232410210212), we get a palindrome (71433611633417).

The spelling of 21201201423205 in words is "twenty-one trillion, two hundred one billion, two hundred one million, four hundred twenty-three thousand, two hundred five".