11981911 has 2 divisors, whose sum is σ = 11981912. Its totient is φ = 11981910.

The previous prime is 11981909. The next prime is 11981917. The reversal of 11981911 is 11918911.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 11981911 - 2¹ = 11981909 is a prime.

Together with 11981909, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11981917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5990955 + 5990956.

It is an arithmetic number, because the mean of its divisors is an integer number (5990956).

Almost surely, 2^11981911 is an apocalyptic number.

11981911 is a deficient number, since it is larger than the sum of its proper divisors (1).

11981911 is an equidigital number, since it uses as much as digits as its factorization.

11981911 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 31.

The square root of 11981911 is about 3461.4897082037. The cubic root of 11981911 is about 228.8277532372.

The spelling of 11981911 in words is "eleven million, nine hundred eighty-one thousand, nine hundred eleven".