11821621 has 4 divisors (see below), whose sum is σ = 13510432. Its totient is φ = 10132812.

The previous prime is 11821583. The next prime is 11821627. The reversal of 11821621 is 12612811.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12612811 = 131 ⋅96281.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11821621 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11821592 and 11821601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11821627) 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, 844395 + ... + 844408.

It is an arithmetic number, because the mean of its divisors is an integer number (3377608).

Almost surely, 2^11821621 is an apocalyptic number.

It is an amenable number.

11821621 is a deficient number, since it is larger than the sum of its proper divisors (1688811).

11821621 is an equidigital number, since it uses as much as digits as its factorization.

11821621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1688810.

The product of its digits is 192, while the sum is 22.

The square root of 11821621 is about 3438.2584254241. The cubic root of 11821621 is about 227.8027752238.

The spelling of 11821621 in words is "eleven million, eight hundred twenty-one thousand, six hundred twenty-one".