21556133434444 has 96 divisors (see below), whose sum is σ = 44173657769472. Its totient is φ = 9011483712000.

The previous prime is 21556133434427. The next prime is 21556133434567. The reversal of 21556133434444 is 44443433165512.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 4168655979 + ... + 4168661149.

It is an arithmetic number, because the mean of its divisors is an integer number (460142268432).

Almost surely, 2^{21556133434444} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21556133434444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22086828884736).

21556133434444 is an abundant number, since it is smaller than the sum of its proper divisors (22617524335028).

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

21556133434444 is a wasteful number, since it uses less digits than its factorization.

21556133434444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9167 (or 9165 counting only the distinct ones).

The product of its digits is 8294400, while the sum is 49.

Adding to 21556133434444 its reverse (44443433165512), we get a palindrome (65999566599956).

The spelling of 21556133434444 in words is "twenty-one trillion, five hundred fifty-six billion, one hundred thirty-three million, four hundred thirty-four thousand, four hundred forty-four".