1181681 has 2 divisors, whose sum is σ = 1181682. Its totient is φ = 1181680.

The previous prime is 1181647. The next prime is 1181699. The reversal of 1181681 is 1861811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1123600 + 58081 = 1060^2 + 241^2 .

It is a cyclic number.

It is not a de Polignac number, because 1181681 - 2⁶ = 1181617 is a prime.

It is a super-2 number, since 2×1181681² = 2792739971522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1181681.

It is not a weakly prime, because it can be changed into another prime (1181611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 590840 + 590841.

It is an arithmetic number, because the mean of its divisors is an integer number (590841).

2^1181681 is an apocalyptic number.

It is an amenable number.

1181681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1181681 is an equidigital number, since it uses as much as digits as its factorization.

1181681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 26.

The square root of 1181681 is about 1087.0515167185. The cubic root of 1181681 is about 105.7223360769.

The spelling of 1181681 in words is "one million, one hundred eighty-one thousand, six hundred eighty-one".