11818721 has 4 divisors (see below), whose sum is σ = 11827200. Its totient is φ = 11810244.

The previous prime is 11818693. The next prime is 11818727. The reversal of 11818721 is 12781811.

11818721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 11818721 - 2¹⁴ = 11802337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11818727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1601 + ... + 5118.

It is an arithmetic number, because the mean of its divisors is an integer number (2956800).

Almost surely, 2^11818721 is an apocalyptic number.

It is an amenable number.

11818721 is a deficient number, since it is larger than the sum of its proper divisors (8479).

11818721 is an equidigital number, since it uses as much as digits as its factorization.

11818721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8478.

The product of its digits is 896, while the sum is 29.

The square root of 11818721 is about 3437.8366744219. The cubic root of 11818721 is about 227.7841460224.

The spelling of 11818721 in words is "eleven million, eight hundred eighteen thousand, seven hundred twenty-one".