11661541 has 4 divisors (see below), whose sum is σ = 12347532. Its totient is φ = 10975552.

The previous prime is 11661523. The next prime is 11661547. The reversal of 11661541 is 14516611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14516611 = 23 ⋅631157.

It can be written as a sum of positive squares in 2 ways, for example, as 4532641 + 7128900 = 2129^2 + 2670^2 .

It is a cyclic number.

It is not a de Polignac number, because 11661541 - 2¹⁷ = 11530469 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11661547) 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 3 ways as a sum of consecutive naturals, for example, 342970 + ... + 343003.

It is an arithmetic number, because the mean of its divisors is an integer number (3086883).

Almost surely, 2^11661541 is an apocalyptic number.

It is an amenable number.

11661541 is a deficient number, since it is larger than the sum of its proper divisors (685991).

11661541 is an equidigital number, since it uses as much as digits as its factorization.

11661541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685990.

The product of its digits is 720, while the sum is 25.

The square root of 11661541 is about 3414.8998521187. The cubic root of 11661541 is about 226.7698508967.

The spelling of 11661541 in words is "eleven million, six hundred sixty-one thousand, five hundred forty-one".