7581661 has 4 divisors (see below), whose sum is σ = 7608924. Its totient is φ = 7554400.

The previous prime is 7581659. The next prime is 7581667. The reversal of 7581661 is 1661857.

7581661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2785561 + 4796100 = 1669^2 + 2190^2 .

It is a cyclic number.

It is not a de Polignac number, because 7581661 - 2¹ = 7581659 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 (7581667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13210 + ... + 13771.

It is an arithmetic number, because the mean of its divisors is an integer number (1902231).

Almost surely, 2^7581661 is an apocalyptic number.

It is an amenable number.

7581661 is a deficient number, since it is larger than the sum of its proper divisors (27263).

7581661 is a wasteful number, since it uses less digits than its factorization.

7581661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27262.

The product of its digits is 10080, while the sum is 34.

The square root of 7581661 is about 2753.4816142477. The cubic root of 7581661 is about 196.4512458170.

The spelling of 7581661 in words is "seven million, five hundred eighty-one thousand, six hundred sixty-one".