11721205 has 4 divisors (see below), whose sum is σ = 14065452. Its totient is φ = 9376960.

The previous prime is 11721187. The next prime is 11721209. The reversal of 11721205 is 50212711.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50212711 = 1223 ⋅41057.

It can be written as a sum of positive squares in 2 ways, for example, as 8868484 + 2852721 = 2978^2 + 1689^2 .

It is not a de Polignac number, because 11721205 - 2⁷ = 11721077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11721209) 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, 1172116 + ... + 1172125.

It is an arithmetic number, because the mean of its divisors is an integer number (3516363).

Almost surely, 2^11721205 is an apocalyptic number.

It is an amenable number.

11721205 is a deficient number, since it is larger than the sum of its proper divisors (2344247).

11721205 is an equidigital number, since it uses as much as digits as its factorization.

11721205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2344246.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 11721205 is about 3423.6245413304. The cubic root of 11721205 is about 227.1559344403.

Adding to 11721205 its reverse (50212711), we get a palindrome (61933916).

The spelling of 11721205 in words is "eleven million, seven hundred twenty-one thousand, two hundred five".