218178009 has 32 divisors (see below), whose sum is σ = 371220480. Its totient is φ = 124059600.

The previous prime is 218177957. The next prime is 218178043. The reversal of 218178009 is 900871812.

It is not a de Polignac number, because 218178009 - 2⁹ = 218177497 is a prime.

It is a super-2 number, since 2×218178009² = 95203287222408162, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (218178209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37144 + ... + 42614.

It is an arithmetic number, because the mean of its divisors is an integer number (11600640).

Almost surely, 2^218178009 is an apocalyptic number.

It is an amenable number.

218178009 is a deficient number, since it is larger than the sum of its proper divisors (153042471).

218178009 is a wasteful number, since it uses less digits than its factorization.

218178009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5698 (or 5692 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 218178009 is about 14770.8499755430. The cubic root of 218178009 is about 602.0099344210.

The spelling of 218178009 in words is "two hundred eighteen million, one hundred seventy-eight thousand, nine".