21221342155365 has 16 divisors (see below), whose sum is σ = 37040888126016. Its totient is φ = 10289135590400.

The previous prime is 21221342155357. The next prime is 21221342155423. The reversal of 21221342155365 is 56355124312212.

It is not a de Polignac number, because 21221342155365 - 2³ = 21221342155357 is a prime.

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, 64307097276 + ... + 64307097605.

It is an arithmetic number, because the mean of its divisors is an integer number (2315055507876).

Almost surely, 2^{21221342155365} is an apocalyptic number.

It is an amenable number.

21221342155365 is a deficient number, since it is larger than the sum of its proper divisors (15819545970651).

21221342155365 is a wasteful number, since it uses less digits than its factorization.

21221342155365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128614194900.

The product of its digits is 432000, while the sum is 42.

Adding to 21221342155365 its reverse (56355124312212), we get a palindrome (77576466467577).

The spelling of 21221342155365 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred forty-two million, one hundred fifty-five thousand, three hundred sixty-five".