21213611605365 has 16 divisors (see below), whose sum is σ = 33948319795200. Its totient is φ = 11311745780672.

The previous prime is 21213611605357. The next prime is 21213611605391. The reversal of 21213611605365 is 56350611631212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21213611605365 - 2³ = 21213611605357 is a prime.

It is a super-2 number, since 2×21213611605365² (a number of 27 digits) contains 22 as substring.

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 15 ways as a sum of consecutive naturals, for example, 136195125 + ... + 136350794.

It is an arithmetic number, because the mean of its divisors is an integer number (2121769987200).

Almost surely, 2^{21213611605365} is an apocalyptic number.

It is an amenable number.

21213611605365 is a deficient number, since it is larger than the sum of its proper divisors (12734708189835).

21213611605365 is a wasteful number, since it uses less digits than its factorization.

21213611605365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272551116.

The product of its (nonzero) digits is 194400, while the sum is 42.

The spelling of 21213611605365 in words is "twenty-one trillion, two hundred thirteen billion, six hundred eleven million, six hundred five thousand, three hundred sixty-five".