11111721 has 4 divisors (see below), whose sum is σ = 14815632. Its totient is φ = 7407812.

The previous prime is 11111707. The next prime is 11111747. The reversal of 11111721 is 12711111.

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.

It is a cyclic number.

It is not a de Polignac number, because 11111721 - 2⁹ = 11111209 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11111721.

It is not an unprimeable number, because it can be changed into a prime (11111701) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1851951 + ... + 1851956.

It is an arithmetic number, because the mean of its divisors is an integer number (3703908).

Almost surely, 2^11111721 is an apocalyptic number.

It is an amenable number.

11111721 is a deficient number, since it is larger than the sum of its proper divisors (3703911).

11111721 is an equidigital number, since it uses as much as digits as its factorization.

11111721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703910.

The product of its digits is 14, while the sum is 15.

The square root of 11111721 is about 3333.4248154113. The cubic root of 11111721 is about 223.1483994165.

Adding to 11111721 its reverse (12711111), we get a palindrome (23822832).

It can be divided in two parts, 111 and 11721, that multiplied together give a palindrome (1301031).

The spelling of 11111721 in words is "eleven million, one hundred eleven thousand, seven hundred twenty-one".