87218155 has 4 divisors (see below), whose sum is σ = 104661792. Its totient is φ = 69774520.

The previous prime is 87218099. The next prime is 87218171. The reversal of 87218155 is 55181278.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-87218155 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 8721811 + ... + 8721820.

It is an arithmetic number, because the mean of its divisors is an integer number (26165448).

Almost surely, 2^87218155 is an apocalyptic number.

87218155 is a deficient number, since it is larger than the sum of its proper divisors (17443637).

87218155 is a wasteful number, since it uses less digits than its factorization.

87218155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17443636.

The product of its digits is 22400, while the sum is 37.

The square root of 87218155 is about 9339.0660667970. The cubic root of 87218155 is about 443.4748190068.

The spelling of 87218155 in words is "eighty-seven million, two hundred eighteen thousand, one hundred fifty-five".