11517721 has 8 divisors (see below), whose sum is σ = 12363624. Its totient is φ = 10690560.

The previous prime is 11517697. The next prime is 11517731. The reversal of 11517721 is 12771511.

It can be written as a sum of positive squares in 4 ways, for example, as 5929225 + 5588496 = 2435^2 + 2364^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11517721 - 2⁵ = 11517689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11517731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3400 + ... + 5881.

It is an arithmetic number, because the mean of its divisors is an integer number (1545453).

Almost surely, 2^11517721 is an apocalyptic number.

It is an amenable number.

11517721 is a deficient number, since it is larger than the sum of its proper divisors (845903).

11517721 is an equidigital number, since it uses as much as digits as its factorization.

11517721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9371.

The product of its digits is 490, while the sum is 25.

The square root of 11517721 is about 3393.7768046824. The cubic root of 11517721 is about 225.8337527471.

The spelling of 11517721 in words is "eleven million, five hundred seventeen thousand, seven hundred twenty-one".