21216361565466 has 24 divisors (see below), whose sum is σ = 45977608471860. Its totient is φ = 7070762817216.

The previous prime is 21216361565461. The next prime is 21216361565479. The reversal of 21216361565466 is 66456516361212.

21216361565466 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 6 + 36 + 1 + 565 + 46 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15586869816441 + 5629491749025 = 3948021^2 + 2372655^2 .

It is not an unprimeable number, because it can be changed into a prime (21216361565461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 113045685 + ... + 113233208.

Almost surely, 2^{21216361565466} is an apocalyptic number.

21216361565466 is an abundant number, since it is smaller than the sum of its proper divisors (24761246906394).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21216361565466 is a wasteful number, since it uses less digits than its factorization.

21216361565466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226284110 (or 226284107 counting only the distinct ones).

The product of its digits is 9331200, while the sum is 54.

The spelling of 21216361565466 in words is "twenty-one trillion, two hundred sixteen billion, three hundred sixty-one million, five hundred sixty-five thousand, four hundred sixty-six".