1166561 has 12 divisors (see below), whose sum is σ = 1327872. Its totient is φ = 1023000.

The previous prime is 1166549. The next prime is 1166563. The reversal of 1166561 is 1656611.

It is not a de Polignac number, because 1166561 - 2⁶ = 1166497 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 1166561.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1166563) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3596 + ... + 3906.

It is an arithmetic number, because the mean of its divisors is an integer number (110656).

2^1166561 is an apocalyptic number.

1166561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1166561 is a deficient number, since it is larger than the sum of its proper divisors (161311).

1166561 is a wasteful number, since it uses less digits than its factorization.

1166561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364 (or 353 counting only the distinct ones).

The product of its digits is 1080, while the sum is 26.

The square root of 1166561 is about 1080.0745344651. The cubic root of 1166561 is about 105.2694816332.

The spelling of 1166561 in words is "one million, one hundred sixty-six thousand, five hundred sixty-one".