7666561 has 4 divisors (see below), whose sum is σ = 8761792. Its totient is φ = 6571332.

The previous prime is 7666559. The next prime is 7666573. The reversal of 7666561 is 1656667.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7666561 - 2¹ = 7666559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7666561.

It is not an unprimeable number, because it can be changed into a prime (7666501) 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, 547605 + ... + 547618.

It is an arithmetic number, because the mean of its divisors is an integer number (2190448).

Almost surely, 2^7666561 is an apocalyptic number.

It is an amenable number.

7666561 is a deficient number, since it is larger than the sum of its proper divisors (1095231).

7666561 is a wasteful number, since it uses less digits than its factorization.

7666561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1095230.

The product of its digits is 45360, while the sum is 37.

The square root of 7666561 is about 2768.8555397492. The cubic root of 7666561 is about 197.1818174218.

The spelling of 7666561 in words is "seven million, six hundred sixty-six thousand, five hundred sixty-one".