21724137959056 has 45 divisors (see below), whose sum is σ = 45577814204379. Its totient is φ = 10026413349888.

The previous prime is 21724137959039. The next prime is 21724137959059. The reversal of 21724137959056 is 65095973142712.

The square root of 21724137959056 is 4660916.

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

It can be written as a sum of positive squares in 4 ways, for example, as 14640449248656 + 7083688710400 = 3826284^2 + 2661520^2 .

It is a super-2 number, since 2×21724137959056² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21724137958985 and 21724137959003.

It is not an unprimeable number, because it can be changed into a prime (21724137959059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 242322816 + ... + 242412448.

Almost surely, 2^{21724137959056} is an apocalyptic number.

21724137959056 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21724137959056 is the 4660916-th square number.

It is an amenable number.

21724137959056 is an abundant number, since it is smaller than the sum of its proper divisors (23853676245323).

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

21724137959056 is an frugal number, since it uses more digits than its factorization.

21724137959056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179300 (or 89648 counting only the distinct ones).

The product of its (nonzero) digits is 28576800, while the sum is 61.

The spelling of 21724137959056 in words is "twenty-one trillion, seven hundred twenty-four billion, one hundred thirty-seven million, nine hundred fifty-nine thousand, fifty-six".