87221665 has 4 divisors (see below), whose sum is σ = 104666004. Its totient is φ = 69777328.

The previous prime is 87221663. The next prime is 87221669. The reversal of 87221665 is 56612278.

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 12278016 + 74943649 = 3504^2 + 8657^2 .

It is a cyclic number.

It is not a de Polignac number, because 87221665 - 2¹ = 87221663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87221663) 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, 8722162 + ... + 8722171.

It is an arithmetic number, because the mean of its divisors is an integer number (26166501).

Almost surely, 2^87221665 is an apocalyptic number.

It is an amenable number.

87221665 is a deficient number, since it is larger than the sum of its proper divisors (17444339).

87221665 is a wasteful number, since it uses less digits than its factorization.

87221665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17444338.

The product of its digits is 40320, while the sum is 37.

The square root of 87221665 is about 9339.2539851960. The cubic root of 87221665 is about 443.4807679813.

The spelling of 87221665 in words is "eighty-seven million, two hundred twenty-one thousand, six hundred sixty-five".