11556421766440 has 128 divisors (see below), whose sum is σ = 27256349352960. Its totient is φ = 4401409982464.

The previous prime is 11556421766399. The next prime is 11556421766473. The reversal of 11556421766440 is 4466712465511.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1495585857 + ... + 1495593583.

It is an arithmetic number, because the mean of its divisors is an integer number (212940229320).

Almost surely, 2^{11556421766440} is an apocalyptic number.

11556421766440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11556421766440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13628174676480).

11556421766440 is an abundant number, since it is smaller than the sum of its proper divisors (15699927586520).

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

11556421766440 is a wasteful number, since it uses less digits than its factorization.

11556421766440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14971 (or 14967 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 52.

The spelling of 11556421766440 in words is "eleven trillion, five hundred fifty-six billion, four hundred twenty-one million, seven hundred sixty-six thousand, four hundred forty".