21660354110216 has 32 divisors (see below), whose sum is σ = 41170554194040. Its totient is φ = 10681547194368.

The previous prime is 21660354110177. The next prime is 21660354110237. The reversal of 21660354110216 is 61201145306612.

It can be written as a sum of positive squares in 4 ways, for example, as 18316773636100 + 3343580474116 = 4279810^2 + 1828546^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21660354110216.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23597000 + ... + 24497736.

Almost surely, 2^{21660354110216} is an apocalyptic number.

It is an amenable number.

21660354110216 is a deficient number, since it is larger than the sum of its proper divisors (19510200083824).

21660354110216 is a wasteful number, since it uses less digits than its factorization.

21660354110216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941993 (or 941989 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 38.

Adding to 21660354110216 its reverse (61201145306612), we get a palindrome (82861499416828).

The spelling of 21660354110216 in words is "twenty-one trillion, six hundred sixty billion, three hundred fifty-four million, one hundred ten thousand, two hundred sixteen".