11721920 has 56 divisors (see below), whose sum is σ = 31906464. Its totient is φ = 4018176.

The previous prime is 11721911. The next prime is 11721947. The reversal of 11721920 is 2912711.

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

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 7 ways as a sum of consecutive naturals, for example, 377 + ... + 4856.

Almost surely, 2^11721920 is an apocalyptic number.

11721920 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 11721920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15953232).

11721920 is an abundant number, since it is smaller than the sum of its proper divisors (20184544).

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

11721920 is an equidigital number, since it uses as much as digits as its factorization.

11721920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5257 (or 5247 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 11721920 is about 3423.7289612351. The cubic root of 11721920 is about 227.1605532257.

The spelling of 11721920 in words is "eleven million, seven hundred twenty-one thousand, nine hundred twenty".