87318521 has 2 divisors, whose sum is σ = 87318522. Its totient is φ = 87318520.

The previous prime is 87318503. The next prime is 87318529. The reversal of 87318521 is 12581378.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66259600 + 21058921 = 8140^2 + 4589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87318521 is a prime.

It is not a weakly prime, because it can be changed into another prime (87318529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43659260 + 43659261.

It is an arithmetic number, because the mean of its divisors is an integer number (43659261).

Almost surely, 2^87318521 is an apocalyptic number.

It is an amenable number.

87318521 is a deficient number, since it is larger than the sum of its proper divisors (1).

87318521 is an equidigital number, since it uses as much as digits as its factorization.

87318521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 35.

The square root of 87318521 is about 9344.4379713282. The cubic root of 87318521 is about 443.6448628523.

Adding to 87318521 its reverse (12581378), we get a palindrome (99899899).

The spelling of 87318521 in words is "eighty-seven million, three hundred eighteen thousand, five hundred twenty-one".