11521665 has 24 divisors (see below), whose sum is σ = 21147048. Its totient is φ = 5783040.

The previous prime is 11521661. The next prime is 11521687. The reversal of 11521665 is 56612511.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3837681 + 7683984 = 1959^2 + 2772^2 .

It is not a de Polignac number, because 11521665 - 2² = 11521661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11521661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6766 + ... + 8295.

It is an arithmetic number, because the mean of its divisors is an integer number (881127).

Almost surely, 2^11521665 is an apocalyptic number.

11521665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

11521665 is a deficient number, since it is larger than the sum of its proper divisors (9625383).

11521665 is a wasteful number, since it uses less digits than its factorization.

11521665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15089 (or 15086 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 11521665 is about 3394.3578184982. The cubic root of 11521665 is about 225.8595271364.

The spelling of 11521665 in words is "eleven million, five hundred twenty-one thousand, six hundred sixty-five".