87217321 has 2 divisors, whose sum is σ = 87217322. Its totient is φ = 87217320.

The previous prime is 87217309. The next prime is 87217337. The reversal of 87217321 is 12371278.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87216921 + 400 = 9339^2 + 20^2 .

It is a cyclic number.

It is not a de Polignac number, because 87217321 - 2¹¹ = 87215273 is a prime.

It is a super-2 number, since 2×87217321² = 15213722164834082, which contains 22 as substring.

It is equal to p_5065087 and since 87217321 and 5065087 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (87217121) 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 as a sum of consecutive naturals, namely, 43608660 + 43608661.

It is an arithmetic number, because the mean of its divisors is an integer number (43608661).

Almost surely, 2^87217321 is an apocalyptic number.

It is an amenable number.

87217321 is a deficient number, since it is larger than the sum of its proper divisors (1).

87217321 is an equidigital number, since it uses as much as digits as its factorization.

87217321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4704, while the sum is 31.

The square root of 87217321 is about 9339.0214155446. The cubic root of 87217321 is about 443.4734054663.

Adding to 87217321 its reverse (12371278), we get a palindrome (99588599).

The spelling of 87217321 in words is "eighty-seven million, two hundred seventeen thousand, three hundred twenty-one".