11807981 has 4 divisors (see below), whose sum is σ = 11814972. Its totient is φ = 11800992.

The previous prime is 11807977. The next prime is 11807989. The reversal of 11807981 is 18970811.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8352100 + 3455881 = 2890^2 + 1859^2 .

It is a cyclic number.

It is not a de Polignac number, because 11807981 - 2² = 11807977 is a prime.

It is a super-2 number, since 2×11807981² = 278856830592722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11807989) 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 3 ways as a sum of consecutive naturals, for example, 791 + ... + 4923.

It is an arithmetic number, because the mean of its divisors is an integer number (2953743).

Almost surely, 2^11807981 is an apocalyptic number.

It is an amenable number.

11807981 is a deficient number, since it is larger than the sum of its proper divisors (6991).

11807981 is an equidigital number, since it uses as much as digits as its factorization.

11807981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6990.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 11807981 is about 3436.2742905653. The cubic root of 11807981 is about 227.7151271852.

The spelling of 11807981 in words is "eleven million, eight hundred seven thousand, nine hundred eighty-one".