21394473173056 has 63 divisors (see below), whose sum is σ = 43274769664791. Its totient is φ = 10494439847424.

The previous prime is 21394473172939. The next prime is 21394473173057. The reversal of 21394473173056 is 65037137449312.

The square root of 21394473173056 is 4625416.

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 53916840000 + 21340556333056 = 232200^2 + 4619584^2 .

It is a super-3 number, since 3×21394473173056³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21394473172988 and 21394473173006.

It is not an unprimeable number, because it can be changed into a prime (21394473173057) 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, 1961170930 + ... + 1961181838.

Almost surely, 2^{21394473173056} is an apocalyptic number.

21394473173056 is the 4625416-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21394473173056

21394473173056 is an abundant number, since it is smaller than the sum of its proper divisors (21880296491735).

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

21394473173056 is an frugal number, since it uses more digits than its factorization.

21394473173056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21936 (or 10964 counting only the distinct ones).

The product of its (nonzero) digits is 11430720, while the sum is 55.

The spelling of 21394473173056 in words is "twenty-one trillion, three hundred ninety-four billion, four hundred seventy-three million, one hundred seventy-three thousand, fifty-six".