87181221 has 8 divisors (see below), whose sum is σ = 120250080. Its totient is φ = 56116592.

The previous prime is 87181189. The next prime is 87181249. The reversal of 87181221 is 12218178.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 87181221 - 2⁵ = 87181189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87181921) 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 7 ways as a sum of consecutive naturals, for example, 500955 + ... + 501128.

It is an arithmetic number, because the mean of its divisors is an integer number (15031260).

Almost surely, 2^87181221 is an apocalyptic number.

It is an amenable number.

87181221 is a deficient number, since it is larger than the sum of its proper divisors (33068859).

87181221 is a wasteful number, since it uses less digits than its factorization.

87181221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002115.

The product of its digits is 1792, while the sum is 30.

The square root of 87181221 is about 9337.0884648267. The cubic root of 87181221 is about 443.4122112025.

Adding to 87181221 its reverse (12218178), we get a palindrome (99399399).

The spelling of 87181221 in words is "eighty-seven million, one hundred eighty-one thousand, two hundred twenty-one".