187936681 has 3 divisors (see below), whose sum is σ = 187950391. Its totient is φ = 187922972.

The previous prime is 187936631. The next prime is 187936687. The reversal of 187936681 is 186639781.

The square root of 187936681 is 13709.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 162333081 + 25603600 = 12741^2 + 5060^2 .

It is not a de Polignac number, because 187936681 - 2¹⁵ = 187903913 is a prime.

It is a super-2 number, since 2×187936681² = 70640392130591522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (187936687) 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 in 2 ways as a sum of consecutive naturals, for example, 6855 + ... + 20563.

Almost surely, 2^187936681 is an apocalyptic number.

187936681 is the 13709-th square number.

187936681 is the 6855-th centered octagonal number.

It is an amenable number.

187936681 is a deficient number, since it is larger than the sum of its proper divisors (13710).

187936681 is an frugal number, since it uses more digits than its factorization.

187936681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27418 (or 13709 counting only the distinct ones).

The product of its digits is 435456, while the sum is 49.

The cubic root of 187936681 is about 572.8011100746.

Multiplying 187936681 by its sum of digits (49), we get a square (9208897369 = 95963²).

The spelling of 187936681 in words is "one hundred eighty-seven million, nine hundred thirty-six thousand, six hundred eighty-one".