1185881681 has 2 divisors, whose sum is σ = 1185881682. Its totient is φ = 1185881680.

The previous prime is 1185881647. The next prime is 1185881701. The reversal of 1185881681 is 1861885811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 786241600 + 399640081 = 28040^2 + 19991^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1185881681 is a prime.

It is a super-2 number, since 2×1185881681² = 2812630722662771522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1185881381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 592940840 + 592940841.

It is an arithmetic number, because the mean of its divisors is an integer number (592940841).

Almost surely, 2^1185881681 is an apocalyptic number.

It is an amenable number.

1185881681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1185881681 is an equidigital number, since it uses as much as digits as its factorization.

1185881681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122880, while the sum is 47.

The square root of 1185881681 is about 34436.6328348171. The cubic root of 1185881681 is about 1058.4746307940.

It can be divided in two parts, 11858 and 81681, that added together give a palindrome (93539).

The spelling of 1185881681 in words is "one billion, one hundred eighty-five million, eight hundred eighty-one thousand, six hundred eighty-one".