218005225 has 9 divisors (see below), whose sum is σ = 270418053. Its totient is φ = 174345120.

The previous prime is 218005219. The next prime is 218005243. The reversal of 218005225 is 522500812.

The square root of 218005225 is 14765.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 8450649 + 209554576 = 2907^2 + 14476^2 .

It is not a de Polignac number, because 218005225 - 2³ = 218005217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 218005225.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 72349 + ... + 75301.

Almost surely, 2^218005225 is an apocalyptic number.

218005225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

218005225 is the 14765-th square number.

218005225 is the 7383-rd centered octagonal number.

It is an amenable number.

218005225 is a deficient number, since it is larger than the sum of its proper divisors (52412828).

218005225 is an frugal number, since it uses more digits than its factorization.

218005225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5916 (or 2958 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The cubic root of 218005225 is about 601.8509737698.

Multiplying 218005225 by its sum of digits (25), we get a square (5450130625 = 73825²).

218005225 divided by its sum of digits (25) gives a square (8720209 = 2953²).

Multiplying 218005225 by its product of nonzero digits (1600), we get a square (348808360000 = 590600²).

The spelling of 218005225 in words is "two hundred eighteen million, five thousand, two hundred twenty-five".