11831721 has 16 divisors (see below), whose sum is σ = 17314560. Its totient is φ = 7127120.

The previous prime is 11831719. The next prime is 11831723. The reversal of 11831721 is 12713811.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (11831719) and next prime (11831723).

It is not a de Polignac number, because 11831721 - 2¹ = 11831719 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11831691 and 11831700.

It is not an unprimeable number, because it can be changed into a prime (11831723) 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 15 ways as a sum of consecutive naturals, for example, 4906 + ... + 6908.

It is an arithmetic number, because the mean of its divisors is an integer number (1082160).

Almost surely, 2^11831721 is an apocalyptic number.

11831721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11831721 is a deficient number, since it is larger than the sum of its proper divisors (5482839).

11831721 is a wasteful number, since it uses less digits than its factorization.

11831721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196.

The product of its digits is 336, while the sum is 24.

The square root of 11831721 is about 3439.7268786926. The cubic root of 11831721 is about 227.8676324628.

The spelling of 11831721 in words is "eleven million, eight hundred thirty-one thousand, seven hundred twenty-one".