11581980 has 48 divisors (see below), whose sum is σ = 32689440. Its totient is φ = 3063808.

The previous prime is 11581979. The next prime is 11581987. The reversal of 11581980 is 8918511.

It is a super-4 number, since 4×11581980⁴ (a number of 29 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11581987) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 7516 + ... + 8924.

It is an arithmetic number, because the mean of its divisors is an integer number (681030).

Almost surely, 2^11581980 is an apocalyptic number.

11581980 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 11581980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16344720).

11581980 is an abundant number, since it is smaller than the sum of its proper divisors (21107460).

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

11581980 is a wasteful number, since it uses less digits than its factorization.

11581980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1558 (or 1556 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 33.

The square root of 11581980 is about 3403.2308179141. The cubic root of 11581980 is about 226.2529602901.

It can be divided in two parts, 11581 and 980, that added together give a triangular number (12561 = T₁₅₈).

The spelling of 11581980 in words is "eleven million, five hundred eighty-one thousand, nine hundred eighty".