187221071 has 4 divisors (see below), whose sum is σ = 193677000. Its totient is φ = 180765144.

The previous prime is 187221061. The next prime is 187221113. The reversal of 187221071 is 170122781.

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

It is a cyclic number.

It is not a de Polignac number, because 187221071 - 2⁶ = 187221007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 6455899 = 187221071 / (1 + 8 + 7 + 2 + 2 + 1 + 0 + 7 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (187221061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3227921 + ... + 3227978.

It is an arithmetic number, because the mean of its divisors is an integer number (48419250).

Almost surely, 2^187221071 is an apocalyptic number.

187221071 is a deficient number, since it is larger than the sum of its proper divisors (6455929).

187221071 is an equidigital number, since it uses as much as digits as its factorization.

187221071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6455928.

The product of its (nonzero) digits is 1568, while the sum is 29.

The square root of 187221071 is about 13682.8750999196. The cubic root of 187221071 is about 572.0731635349.

The spelling of 187221071 in words is "one hundred eighty-seven million, two hundred twenty-one thousand, seventy-one".