188087681 has 2 divisors, whose sum is σ = 188087682. Its totient is φ = 188087680.

The previous prime is 188087671. The next prime is 188087701. The reversal of 188087681 is 186780881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154157056 + 33930625 = 12416^2 + 5825^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-188087681 is a prime.

It is a super-2 number, since 2×188087681² = 70753951487915522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (188087621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94043840 + 94043841.

It is an arithmetic number, because the mean of its divisors is an integer number (94043841).

Almost surely, 2^188087681 is an apocalyptic number.

It is an amenable number.

188087681 is a deficient number, since it is larger than the sum of its proper divisors (1).

188087681 is an equidigital number, since it uses as much as digits as its factorization.

188087681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172032, while the sum is 47.

The square root of 188087681 is about 13714.5062251617. The cubic root of 188087681 is about 572.9544770010.

The spelling of 188087681 in words is "one hundred eighty-eight million, eighty-seven thousand, six hundred eighty-one".