21213363251165 has 32 divisors (see below), whose sum is σ = 26615086652160. Its totient is φ = 16200907075584.

The previous prime is 21213363251111. The next prime is 21213363251173. The reversal of 21213363251165 is 56115236331212.

It is a cyclic number.

It is not a de Polignac number, because 21213363251165 - 2¹⁴ = 21213363234781 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 301681031 + ... + 301751339.

It is an arithmetic number, because the mean of its divisors is an integer number (831721457880).

Almost surely, 2^{21213363251165} is an apocalyptic number.

It is an amenable number.

21213363251165 is a deficient number, since it is larger than the sum of its proper divisors (5401723400995).

21213363251165 is a wasteful number, since it uses less digits than its factorization.

21213363251165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75461.

The product of its digits is 194400, while the sum is 41.

Adding to 21213363251165 its reverse (56115236331212), we get a palindrome (77328599582377).

The spelling of 21213363251165 in words is "twenty-one trillion, two hundred thirteen billion, three hundred sixty-three million, two hundred fifty-one thousand, one hundred sixty-five".