11981478528 has 384 divisors, whose sum is σ = 38093328000. Its totient is φ = 3741437952.

The previous prime is 11981478511. The next prime is 11981478563. The reversal of 11981478528 is 82587418911.

11981478528 is a `hidden beast` number, since 11 + 98 + 14 + 7 + 8 + 528 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 33374413 + ... + 33374771.

It is an arithmetic number, because the mean of its divisors is an integer number (99201375).

Almost surely, 2^11981478528 is an apocalyptic number.

11981478528 is a gapful number since it is divisible by the number (18) 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 11981478528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19046664000).

11981478528 is an abundant number, since it is smaller than the sum of its proper divisors (26111849472).

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

11981478528 is an equidigital number, since it uses as much as digits as its factorization.

11981478528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 430 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 54.

The spelling of 11981478528 in words is "eleven billion, nine hundred eighty-one million, four hundred seventy-eight thousand, five hundred twenty-eight".