11681921 has 8 divisors (see below), whose sum is σ = 11839464. Its totient is φ = 11525760.

The previous prime is 11681911. The next prime is 11681933. The reversal of 11681921 is 12918611.

It can be written as a sum of positive squares in 4 ways, for example, as 923521 + 10758400 = 961^2 + 3280^2 .

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 11681921 - 2¹⁰ = 11680897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11681911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42035 + ... + 42311.

It is an arithmetic number, because the mean of its divisors is an integer number (1479933).

Almost surely, 2^11681921 is an apocalyptic number.

It is an amenable number.

11681921 is a deficient number, since it is larger than the sum of its proper divisors (157543).

11681921 is a wasteful number, since it uses less digits than its factorization.

11681921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691.

The product of its digits is 864, while the sum is 29.

The square root of 11681921 is about 3417.8825316269. The cubic root of 11681921 is about 226.9018768990.

The spelling of 11681921 in words is "eleven million, six hundred eighty-one thousand, nine hundred twenty-one".