11971521 has 12 divisors (see below), whose sum is σ = 17390100. Its totient is φ = 7935840.

The previous prime is 11971517. The next prime is 11971529. The reversal of 11971521 is 12517911.

It can be written as a sum of positive squares in 2 ways, for example, as 3186225 + 8785296 = 1785^2 + 2964^2 .

It is not a de Polignac number, because 11971521 - 2² = 11971517 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11971529) 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 11 ways as a sum of consecutive naturals, for example, 2046 + ... + 5303.

It is an arithmetic number, because the mean of its divisors is an integer number (1449175).

Almost surely, 2^11971521 is an apocalyptic number.

It is an amenable number.

11971521 is a deficient number, since it is larger than the sum of its proper divisors (5418579).

11971521 is a wasteful number, since it uses less digits than its factorization.

11971521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7536 (or 7533 counting only the distinct ones).

The product of its digits is 630, while the sum is 27.

The square root of 11971521 is about 3459.9885837962. The cubic root of 11971521 is about 228.7615921743.

The spelling of 11971521 in words is "eleven million, nine hundred seventy-one thousand, five hundred twenty-one".