11821421 has 4 divisors (see below), whose sum is σ = 11859744. Its totient is φ = 11783100.

The previous prime is 11821399. The next prime is 11821427. The reversal of 11821421 is 12412811.

11821421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a de Polignac number, because none of the positive numbers 2^k-11821421 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11821393 and 11821402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11821427) 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, 18695 + ... + 19316.

It is an arithmetic number, because the mean of its divisors is an integer number (2964936).

Almost surely, 2^11821421 is an apocalyptic number.

It is an amenable number.

11821421 is a deficient number, since it is larger than the sum of its proper divisors (38323).

11821421 is an equidigital number, since it uses as much as digits as its factorization.

11821421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38322.

The product of its digits is 128, while the sum is 20.

The square root of 11821421 is about 3438.2293408090. The cubic root of 11821421 is about 227.8014905491.

The spelling of 11821421 in words is "eleven million, eight hundred twenty-one thousand, four hundred twenty-one".