11981971 has 2 divisors, whose sum is σ = 11981972. Its totient is φ = 11981970.

The previous prime is 11981941. The next prime is 11981999. The reversal of 11981971 is 17918911.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11981971 - 2¹³ = 11973779 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11981971.

It is not a weakly prime, because it can be changed into another prime (11981911) 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 as a sum of consecutive naturals, namely, 5990985 + 5990986.

It is an arithmetic number, because the mean of its divisors is an integer number (5990986).

Almost surely, 2^11981971 is an apocalyptic number.

11981971 is a deficient number, since it is larger than the sum of its proper divisors (1).

11981971 is an equidigital number, since it uses as much as digits as its factorization.

11981971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 37.

The square root of 11981971 is about 3461.4983749816. The cubic root of 11981971 is about 228.8281351920.

The spelling of 11981971 in words is "eleven million, nine hundred eighty-one thousand, nine hundred seventy-one".