11721840 has 180 divisors, whose sum is σ = 41798664. Its totient is φ = 2715648.

The previous prime is 11721839. The next prime is 11721869. The reversal of 11721840 is 4812711.

11721840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 11721840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 689512 + ... + 689528.

Almost surely, 2^11721840 is an apocalyptic number.

11721840 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 11721840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20899332).

11721840 is an abundant number, since it is smaller than the sum of its proper divisors (30076824).

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

11721840 is a wasteful number, since it uses less digits than its factorization.

11721840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 11721840 is about 3423.7172780474. The cubic root of 11721840 is about 227.1600364478.

It can be divided in two parts, 11721 and 840, that added together give a triangular number (12561 = T₁₅₈).

The spelling of 11721840 in words is "eleven million, seven hundred twenty-one thousand, eight hundred forty".