187864081 has 2 divisors, whose sum is σ = 187864082. Its totient is φ = 187864080.

The previous prime is 187864013. The next prime is 187864099. The reversal of 187864081 is 180468781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151683856 + 36180225 = 12316^2 + 6015^2 .

It is an emirp because it is prime and its reverse (180468781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 187864081 - 2⁷ = 187863953 is a prime.

It is a super-2 number, since 2×187864081² = 70585825859949122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (187861081) 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, 93932040 + 93932041.

It is an arithmetic number, because the mean of its divisors is an integer number (93932041).

Almost surely, 2^187864081 is an apocalyptic number.

It is an amenable number.

187864081 is a deficient number, since it is larger than the sum of its proper divisors (1).

187864081 is an equidigital number, since it uses as much as digits as its factorization.

187864081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 86016, while the sum is 43.

The square root of 187864081 is about 13706.3518486868. The cubic root of 187864081 is about 572.7273428243.

The spelling of 187864081 in words is "one hundred eighty-seven million, eight hundred sixty-four thousand, eighty-one".