1166540581 has 2 divisors, whose sum is σ = 1166540582. Its totient is φ = 1166540580.

The previous prime is 1166540567. The next prime is 1166540603. The reversal of 1166540581 is 1850456611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1085702500 + 80838081 = 32950^2 + 8991^2 .

It is a cyclic number.

It is not a de Polignac number, because 1166540581 - 2⁹ = 1166540069 is a prime.

It is a super-2 number, since 2×1166540581² = 2721633854239635122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1166540581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1166540281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583270290 + 583270291.

It is an arithmetic number, because the mean of its divisors is an integer number (583270291).

Almost surely, 2^1166540581 is an apocalyptic number.

It is an amenable number.

1166540581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166540581 is an equidigital number, since it uses as much as digits as its factorization.

1166540581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28800, while the sum is 37.

The square root of 1166540581 is about 34154.6567981586. The cubic root of 1166540581 is about 1052.6886743188.

The spelling of 1166540581 in words is "one billion, one hundred sixty-six million, five hundred forty thousand, five hundred eighty-one".