218138004 has 54 divisors (see below), whose sum is σ = 641434794. Its totient is φ = 62324640.

The previous prime is 218137987. The next prime is 218138023. The reversal of 218138004 is 400831812.

It can be written as a sum of positive squares in only one way, i.e., 143280900 + 74857104 = 11970^2 + 8652^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 60067 + ... + 63594.

Almost surely, 2^218138004 is an apocalyptic number.

It is an amenable number.

218138004 is an abundant number, since it is smaller than the sum of its proper divisors (423296790).

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

218138004 is a wasteful number, since it uses less digits than its factorization.

218138004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123685 (or 123673 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 218138004 is about 14769.4957259888. The cubic root of 218138004 is about 601.9731374348.

Adding to 218138004 its reverse (400831812), we get a palindrome (618969816).

The spelling of 218138004 in words is "two hundred eighteen million, one hundred thirty-eight thousand, four".