11820721 has 8 divisors (see below), whose sum is σ = 12920544. Its totient is φ = 10725120.

The previous prime is 11820707. The next prime is 11820727. The reversal of 11820721 is 12702811.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11820721 - 2⁹ = 11820209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11820692 and 11820701.

It is not an unprimeable number, because it can be changed into a prime (11820727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9105 + ... + 10321.

It is an arithmetic number, because the mean of its divisors is an integer number (1615068).

Almost surely, 2^11820721 is an apocalyptic number.

11820721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11820721 is a deficient number, since it is larger than the sum of its proper divisors (1099823).

11820721 is a wasteful number, since it uses less digits than its factorization.

11820721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2111.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 11820721 is about 3438.1275427186. The cubic root of 11820721 is about 227.7969940736.

The spelling of 11820721 in words is "eleven million, eight hundred twenty thousand, seven hundred twenty-one".