21417560223921 has 27 divisors (see below), whose sum is σ = 31289787573889. Its totient is φ = 14117127807552.

The previous prime is 21417560223893. The next prime is 21417560223929. The reversal of 21417560223921 is 12932206571412.

The square root of 21417560223921 is 4627911.

It is a perfect power (a square), and thus also a powerful number.

21417560223921 is a `hidden beast` number, since 2 + 1 + 4 + 1 + 7 + 5 + 602 + 2 + 39 + 2 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 12956652216225 + 8460908007696 = 3599535^2 + 2908764^2 .

It is not a de Polignac number, because 21417560223921 - 2¹⁹ = 21417559699633 is a prime.

It is a super-2 number, since 2×21417560223921² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21417560223929) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1235643571 + ... + 1235660903.

Almost surely, 2^{21417560223921} is an apocalyptic number.

21417560223921 is the 4627911-st square number.

21417560223921 is the 2313956-th centered octagonal number.

It is an amenable number.

21417560223921 is a deficient number, since it is larger than the sum of its proper divisors (9872227349968).

21417560223921 is an frugal number, since it uses more digits than its factorization.

21417560223921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34850 (or 17425 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21417560223921 in words is "twenty-one trillion, four hundred seventeen billion, five hundred sixty million, two hundred twenty-three thousand, nine hundred twenty-one".