218961225 has 144 divisors (see below), whose sum is σ = 491079680. Its totient is φ = 94478400.

The previous prime is 218961217. The next prime is 218961229. The reversal of 218961225 is 522169812.

218961225 is a `hidden beast` number, since 2 + 18 + 9 + 612 + 25 = 666.

It is not a de Polignac number, because 218961225 - 2³ = 218961217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 218961225.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218961229) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 807840 + ... + 808110.

Almost surely, 2^218961225 is an apocalyptic number.

218961225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

218961225 is an abundant number, since it is smaller than the sum of its proper divisors (272118455).

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

218961225 is a wasteful number, since it uses less digits than its factorization.

218961225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 305 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 218961225 is about 14797.3384431120. The cubic root of 218961225 is about 602.7294397699.

The spelling of 218961225 in words is "two hundred eighteen million, nine hundred sixty-one thousand, two hundred twenty-five".