509172218 has 4 divisors (see below), whose sum is σ = 763758330. Its totient is φ = 254586108.

The previous prime is 509172211. The next prime is 509172263. The reversal of 509172218 is 812271905.

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

It can be written as a sum of positive squares in only one way, i.e., 482988529 + 26183689 = 21977^2 + 5117^2 .

It is not an unprimeable number, because it can be changed into a prime (509172211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127293053 + ... + 127293056.

Almost surely, 2^509172218 is an apocalyptic number.

509172218 is a deficient number, since it is larger than the sum of its proper divisors (254586112).

509172218 is a wasteful number, since it uses less digits than its factorization.

509172218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254586111.

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 509172218 is about 22564.8447368911. The cubic root of 509172218 is about 798.5244770883.

It can be divided in two parts, 50917 and 2218, that added together give a palindrome (53135).

The spelling of 509172218 in words is "five hundred nine million, one hundred seventy-two thousand, two hundred eighteen".