1166406561 has 28 divisors (see below), whose sum is σ = 1840874320. Its totient is φ = 736669080.

The previous prime is 1166406517. The next prime is 1166406569. The reversal of 1166406561 is 1656046611.

It is a happy number.

1166406561 is a `hidden beast` number, since 1 + 1 + 6 + 640 + 6 + 5 + 6 + 1 = 666.

It is not a de Polignac number, because 1166406561 - 2⁹ = 1166406049 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1166406569) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 28255 + ... + 55956.

Almost surely, 2^1166406561 is an apocalyptic number.

It is an amenable number.

1166406561 is a deficient number, since it is larger than the sum of its proper divisors (674467759).

1166406561 is an frugal number, since it uses more digits than its factorization.

1166406561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84248 (or 84233 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 1166406561 is about 34152.6947838673. The cubic root of 1166406561 is about 1052.6483594649.

It can be divided in two parts, 116640 and 6561, that added together give a square (123201 = 351²).

The spelling of 1166406561 in words is "one billion, one hundred sixty-six million, four hundred six thousand, five hundred sixty-one".