87173213 has 2 divisors, whose sum is σ = 87173214. Its totient is φ = 87173212.

The previous prime is 87173189. The next prime is 87173227. The reversal of 87173213 is 31237178.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 86899684 + 273529 = 9322^2 + 523^2 .

It is a cyclic number.

It is not a de Polignac number, because 87173213 - 2²⁰ = 86124637 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 87173213.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87173293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43586606 + 43586607.

It is an arithmetic number, because the mean of its divisors is an integer number (43586607).

Almost surely, 2^87173213 is an apocalyptic number.

It is an amenable number.

87173213 is a deficient number, since it is larger than the sum of its proper divisors (1).

87173213 is an equidigital number, since it uses as much as digits as its factorization.

87173213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 32.

The square root of 87173213 is about 9336.6596275113. The cubic root of 87173213 is about 443.3986342965.

The spelling of 87173213 in words is "eighty-seven million, one hundred seventy-three thousand, two hundred thirteen".