218215172 has 24 divisors (see below), whose sum is σ = 445718784. Its totient is φ = 91530432.

The previous prime is 218215157. The next prime is 218215189. The reversal of 218215172 is 271512812.

It is a super-2 number, since 2×218215172² = 95235722581979168, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81593 + ... + 84224.

It is an arithmetic number, because the mean of its divisors is an integer number (18571616).

Almost surely, 2^218215172 is an apocalyptic number.

It is an amenable number.

218215172 is an abundant number, since it is smaller than the sum of its proper divisors (227503612).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218215172 is a wasteful number, since it uses less digits than its factorization.

218215172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165875 (or 165873 counting only the distinct ones).

The product of its digits is 2240, while the sum is 29.

The square root of 218215172 is about 14772.1079064567. The cubic root of 218215172 is about 602.0441132782.

Adding to 218215172 its reverse (271512812), we get a palindrome (489727984).

The spelling of 218215172 in words is "two hundred eighteen million, two hundred fifteen thousand, one hundred seventy-two".