11811520 has 56 divisors (see below), whose sum is σ = 32150304. Its totient is φ = 4048896.

The previous prime is 11811509. The next prime is 11811539. The reversal of 11811520 is 2511811.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (56).

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, 397 + ... + 4876.

Almost surely, 2^11811520 is an apocalyptic number.

11811520 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 11811520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16075152).

11811520 is an abundant number, since it is smaller than the sum of its proper divisors (20338784).

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

11811520 is an equidigital number, since it uses as much as digits as its factorization.

11811520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5297 (or 5287 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 19.

The square root of 11811520 is about 3436.7891992381. The cubic root of 11811520 is about 227.7378746060.

It can be divided in two parts, 1181 and 1520, that added together give a triangular number (2701 = T₇₃).

The spelling of 11811520 in words is "eleven million, eight hundred eleven thousand, five hundred twenty".