187444721 has 2 divisors, whose sum is σ = 187444722. Its totient is φ = 187444720.

The previous prime is 187444679. The next prime is 187444781. The reversal of 187444721 is 127444781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162843121 + 24601600 = 12761^2 + 4960^2 .

It is an emirp because it is prime and its reverse (127444781) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187444721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (187444781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93722360 + 93722361.

It is an arithmetic number, because the mean of its divisors is an integer number (93722361).

Almost surely, 2^187444721 is an apocalyptic number.

It is an amenable number.

187444721 is a deficient number, since it is larger than the sum of its proper divisors (1).

187444721 is an equidigital number, since it uses as much as digits as its factorization.

187444721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 50176, while the sum is 38.

The square root of 187444721 is about 13691.0452851490. The cubic root of 187444721 is about 572.3008680515.

The spelling of 187444721 in words is "one hundred eighty-seven million, four hundred forty-four thousand, seven hundred twenty-one".