11821281 has 4 divisors (see below), whose sum is σ = 15761712. Its totient is φ = 7880852.

The previous prime is 11821267. The next prime is 11821283. The reversal of 11821281 is 18212811.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 11821281 - 2⁹ = 11820769 is a prime.

It is a super-2 number, since 2×11821281² = 279485368961922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11821283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1970211 + ... + 1970216.

It is an arithmetic number, because the mean of its divisors is an integer number (3940428).

Almost surely, 2^11821281 is an apocalyptic number.

It is an amenable number.

11821281 is a deficient number, since it is larger than the sum of its proper divisors (3940431).

11821281 is an equidigital number, since it uses as much as digits as its factorization.

11821281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3940430.

The product of its digits is 256, while the sum is 24.

The square root of 11821281 is about 3438.2089814320. The cubic root of 11821281 is about 227.8005912682.

The spelling of 11821281 in words is "eleven million, eight hundred twenty-one thousand, two hundred eighty-one".