11961881 has 4 divisors (see below), whose sum is σ = 12049332. Its totient is φ = 11874432.

The previous prime is 11961871. The next prime is 11961899. The reversal of 11961881 is 18816911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18816911 = 29 ⋅648859.

It can be written as a sum of positive squares in 2 ways, for example, as 3312400 + 8649481 = 1820^2 + 2941^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11961881 is a prime.

It is a super-2 number, since 2×11961881² = 286173194116322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11961821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43520 + ... + 43793.

It is an arithmetic number, because the mean of its divisors is an integer number (3012333).

Almost surely, 2^11961881 is an apocalyptic number.

It is an amenable number.

11961881 is a deficient number, since it is larger than the sum of its proper divisors (87451).

11961881 is an equidigital number, since it uses as much as digits as its factorization.

11961881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87450.

The product of its digits is 3456, while the sum is 35.

The square root of 11961881 is about 3458.5952350629. The cubic root of 11961881 is about 228.7001726900.

The spelling of 11961881 in words is "eleven million, nine hundred sixty-one thousand, eight hundred eighty-one".