218425 has 6 divisors (see below), whose sum is σ = 270878. Its totient is φ = 174720.

The previous prime is 218423. The next prime is 218437. The reversal of 218425 is 524812.

218425 = 40² + 41² + ... + 89².

It can be written as a sum of positive squares in 3 ways, for example, as 7744 + 210681 = 88^2 + 459^2 .

It is not a de Polignac number, because 218425 - 2¹ = 218423 is a prime.

It is a Duffinian number.

218425 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 218396 and 218405.

It is not an unprimeable number, because it can be changed into a prime (218423) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4344 + ... + 4393.

2²¹⁸⁴²⁵ is an apocalyptic number.

218425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

218425 is a deficient number, since it is larger than the sum of its proper divisors (52453).

218425 is an equidigital number, since it uses as much as digits as its factorization.

218425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8747 (or 8742 counting only the distinct ones).

The product of its digits is 640, while the sum is 22.

The square root of 218425 is about 467.3596045873. The cubic root of 218425 is about 60.2237019577.

It can be divided in two parts, 2184 and 25, that added together give a square (2209 = 47²).

The spelling of 218425 in words is "two hundred eighteen thousand, four hundred twenty-five".