11981623680 has 640 divisors, whose sum is σ = 48145648320. Its totient is φ = 2817441792.

The previous prime is 11981623553. The next prime is 11981623691. The reversal of 11981623680 is 8632618911.

11981623680 is a `hidden beast` number, since 1 + 19 + 8 + 1 + 623 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 15499774 + ... + 15500546.

Almost surely, 2^11981623680 is an apocalyptic number.

11981623680 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 11981623680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24072824160).

11981623680 is an abundant number, since it is smaller than the sum of its proper divisors (36164024640).

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

11981623680 is a wasteful number, since it uses less digits than its factorization.

11981623680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 11981623680 in words is "eleven billion, nine hundred eighty-one million, six hundred twenty-three thousand, six hundred eighty".