11913991 has 8 divisors (see below), whose sum is σ = 12690864. Its totient is φ = 11145600.

The previous prime is 11913959. The next prime is 11914003. The reversal of 11913991 is 19931911.

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 11913991 - 2⁵ = 11913959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11913091) 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, 916 + ... + 4966.

It is an arithmetic number, because the mean of its divisors is an integer number (1586358).

Almost surely, 2^11913991 is an apocalyptic number.

11913991 is a deficient number, since it is larger than the sum of its proper divisors (776873).

11913991 is a wasteful number, since it uses less digits than its factorization.

11913991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4241.

The product of its digits is 2187, while the sum is 34.

The square root of 11913991 is about 3451.6649605661. The cubic root of 11913991 is about 228.3945602171.

The spelling of 11913991 in words is "eleven million, nine hundred thirteen thousand, nine hundred ninety-one".