12555533440 has 64 divisors (see below), whose sum is σ = 30148148160. Its totient is φ = 5000031232.

The previous prime is 12555533381. The next prime is 12555533461. The reversal of 12555533440 is 4433555521.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 12555533440.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102069 + ... + 188491.

It is an arithmetic number, because the mean of its divisors is an integer number (471064815).

Almost surely, 2^12555533440 is an apocalyptic number.

12555533440 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 12555533440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15074074080).

12555533440 is an abundant number, since it is smaller than the sum of its proper divisors (17592614720).

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

12555533440 is an equidigital number, since it uses as much as digits as its factorization.

12555533440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86669 (or 86657 counting only the distinct ones).

The product of its (nonzero) digits is 180000, while the sum is 37.

The spelling of 12555533440 in words is "twelve billion, five hundred fifty-five million, five hundred thirty-three thousand, four hundred forty".