187340821 has 4 divisors (see below), whose sum is σ = 190412044. Its totient is φ = 184269600.

The previous prime is 187340801. The next prime is 187340831. The reversal of 187340821 is 128043781.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5225796 + 182115025 = 2286^2 + 13495^2 .

It is a cyclic number.

It is not a de Polignac number, because 187340821 - 2¹⁵ = 187308053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (187340801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1535520 + ... + 1535641.

It is an arithmetic number, because the mean of its divisors is an integer number (47603011).

Almost surely, 2^187340821 is an apocalyptic number.

It is an amenable number.

187340821 is a deficient number, since it is larger than the sum of its proper divisors (3071223).

187340821 is an equidigital number, since it uses as much as digits as its factorization.

187340821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3071222.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 187340821 is about 13687.2503082248. The cubic root of 187340821 is about 572.1951070041.

The spelling of 187340821 in words is "one hundred eighty-seven million, three hundred forty thousand, eight hundred twenty-one".