187381691 has 8 divisors (see below), whose sum is σ = 217661664. Its totient is φ = 157979520.

The previous prime is 187381679. The next prime is 187381693. The reversal of 187381691 is 196183781.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187381691 is a prime.

It is a super-2 number, since 2×187381691² = 70223796244038962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (187381693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 218990 + ... + 219843.

It is an arithmetic number, because the mean of its divisors is an integer number (27207708).

Almost surely, 2^187381691 is an apocalyptic number.

187381691 is a deficient number, since it is larger than the sum of its proper divisors (30279973).

187381691 is an equidigital number, since it uses as much as digits as its factorization.

187381691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438901.

The product of its digits is 72576, while the sum is 44.

The square root of 187381691 is about 13688.7432220785. The cubic root of 187381691 is about 572.2367137283.

The spelling of 187381691 in words is "one hundred eighty-seven million, three hundred eighty-one thousand, six hundred ninety-one".