11111921 has 4 divisors (see below), whose sum is σ = 11595072. Its totient is φ = 10628772.

The previous prime is 11111911. The next prime is 11111923. The reversal of 11111921 is 12911111.

It is a happy number.

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 an emirpimes, since its reverse is a distinct semiprime: 12911111 = 743 ⋅17377.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11111921 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11111921.

It is not an unprimeable number, because it can be changed into a prime (11111923) 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 3 ways as a sum of consecutive naturals, for example, 241541 + ... + 241586.

It is an arithmetic number, because the mean of its divisors is an integer number (2898768).

Almost surely, 2^11111921 is an apocalyptic number.

It is an amenable number.

11111921 is a deficient number, since it is larger than the sum of its proper divisors (483151).

11111921 is an equidigital number, since it uses as much as digits as its factorization.

11111921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 483150.

The product of its digits is 18, while the sum is 17.

The square root of 11111921 is about 3333.4548144530. The cubic root of 11111921 is about 223.1497382254.

It can be divided in two parts, 111 and 11921, that multiplied together give a palindrome (1323231).

The spelling of 11111921 in words is "eleven million, one hundred eleven thousand, nine hundred twenty-one".