11851721 has 4 divisors (see below), whose sum is σ = 13544832. Its totient is φ = 10158612.

The previous prime is 11851681. The next prime is 11851753. The reversal of 11851721 is 12715811.

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: 12715811 = 1759 ⋅7229.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11851721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11851621) 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, 846545 + ... + 846558.

It is an arithmetic number, because the mean of its divisors is an integer number (3386208).

Almost surely, 2^11851721 is an apocalyptic number.

It is an amenable number.

11851721 is a deficient number, since it is larger than the sum of its proper divisors (1693111).

11851721 is an equidigital number, since it uses as much as digits as its factorization.

11851721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1693110.

The product of its digits is 560, while the sum is 26.

The square root of 11851721 is about 3442.6328587289. The cubic root of 11851721 is about 227.9959538114.

The spelling of 11851721 in words is "eleven million, eight hundred fifty-one thousand, seven hundred twenty-one".