1161781 has 2 divisors, whose sum is σ = 1161782. Its totient is φ = 1161780.

The previous prime is 1161767. The next prime is 1161791. The reversal of 1161781 is 1871611.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1134225 + 27556 = 1065^2 + 166^2 .

It is a cyclic number.

It is not a de Polignac number, because 1161781 - 2⁵ = 1161749 is a prime.

It is a super-2 number, since 2×1161781² = 2699470183922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1161761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580890 + 580891.

It is an arithmetic number, because the mean of its divisors is an integer number (580891).

2^1161781 is an apocalyptic number.

It is an amenable number.

1161781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161781 is an equidigital number, since it uses as much as digits as its factorization.

1161781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 336, while the sum is 25.

The square root of 1161781 is about 1077.8594528045. The cubic root of 1161781 is about 105.1255037460.

The spelling of 1161781 in words is "one million, one hundred sixty-one thousand, seven hundred eighty-one".