21665215371933 has 48 divisors (see below), whose sum is σ = 36017918117376. Its totient is φ = 12292616194560.

The previous prime is 21665215371929. The next prime is 21665215372039. The reversal of 21665215371933 is 33917351256612.

21665215371933 is a `hidden beast` number, since 2 + 1 + 6 + 65 + 2 + 1 + 537 + 19 + 33 = 666.

It is not a de Polignac number, because 21665215371933 - 2² = 21665215371929 is a prime.

It is a super-2 number, since 2×21665215371933² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21665215371933.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21665215371923) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13305253 + ... + 14844533.

It is an arithmetic number, because the mean of its divisors is an integer number (750373294112).

Almost surely, 2^{21665215371933} is an apocalyptic number.

It is an amenable number.

21665215371933 is a deficient number, since it is larger than the sum of its proper divisors (14352702745443).

21665215371933 is a wasteful number, since it uses less digits than its factorization.

21665215371933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540874 (or 1540871 counting only the distinct ones).

The product of its digits is 6123600, while the sum is 54.

The spelling of 21665215371933 in words is "twenty-one trillion, six hundred sixty-five billion, two hundred fifteen million, three hundred seventy-one thousand, nine hundred thirty-three".