11921891 has 8 divisors (see below), whose sum is σ = 12096000. Its totient is φ = 11749320.

The previous prime is 11921867. The next prime is 11921933. The reversal of 11921891 is 19812911.

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 11921891 - 2⁶ = 11921827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11921851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27446 + ... + 27876.

It is an arithmetic number, because the mean of its divisors is an integer number (1512000).

Almost surely, 2^11921891 is an apocalyptic number.

11921891 is a deficient number, since it is larger than the sum of its proper divisors (174109).

11921891 is a wasteful number, since it uses less digits than its factorization.

11921891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769.

The product of its digits is 1296, while the sum is 32.

The square root of 11921891 is about 3452.8091461881. The cubic root of 11921891 is about 228.4450308044.

The spelling of 11921891 in words is "eleven million, nine hundred twenty-one thousand, eight hundred ninety-one".