187997081 has 2 divisors, whose sum is σ = 187997082. Its totient is φ = 187997080.

The previous prime is 187997063. The next prime is 187997107. The reversal of 187997081 is 180799781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106275481 + 81721600 = 10309^2 + 9040^2 .

It is a cyclic number.

It is not a de Polignac number, because 187997081 - 2²⁶ = 120888217 is a prime.

It is a super-2 number, since 2×187997081² = 70685804929041122, 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 (187997041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93998540 + 93998541.

It is an arithmetic number, because the mean of its divisors is an integer number (93998541).

Almost surely, 2^187997081 is an apocalyptic number.

It is an amenable number.

187997081 is a deficient number, since it is larger than the sum of its proper divisors (1).

187997081 is an equidigital number, since it uses as much as digits as its factorization.

187997081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 50.

The square root of 187997081 is about 13711.2027554114. The cubic root of 187997081 is about 572.8624666996.

The spelling of 187997081 in words is "one hundred eighty-seven million, nine hundred ninety-seven thousand, eighty-one".