187513981 has 2 divisors, whose sum is σ = 187513982. Its totient is φ = 187513980.

The previous prime is 187513897. The next prime is 187513999. The reversal of 187513981 is 189315781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 145588356 + 41925625 = 12066^2 + 6475^2 .

It is a cyclic number.

It is not a de Polignac number, because 187513981 - 2¹⁵ = 187481213 is a prime.

It is a super-2 number, since 2×187513981² = 70322986140936722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (187511981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93756990 + 93756991.

It is an arithmetic number, because the mean of its divisors is an integer number (93756991).

Almost surely, 2^187513981 is an apocalyptic number.

It is an amenable number.

187513981 is a deficient number, since it is larger than the sum of its proper divisors (1).

187513981 is an equidigital number, since it uses as much as digits as its factorization.

187513981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 43.

The square root of 187513981 is about 13693.5744420513. The cubic root of 187513981 is about 572.3713469229.

The spelling of 187513981 in words is "one hundred eighty-seven million, five hundred thirteen thousand, nine hundred eighty-one".