218861649 has 32 divisors (see below), whose sum is σ = 334078080. Its totient is φ = 141523200.

The previous prime is 218861641. The next prime is 218861653. The reversal of 218861649 is 946168812.

218861649 is a `hidden beast` number, since 21 + 8 + 8 + 616 + 4 + 9 = 666.

It is not a de Polignac number, because 218861649 - 2³ = 218861641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (218861641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 233109 + ... + 234045.

It is an arithmetic number, because the mean of its divisors is an integer number (10439940).

Almost surely, 2^218861649 is an apocalyptic number.

It is an amenable number.

218861649 is a deficient number, since it is larger than the sum of its proper divisors (115216431).

218861649 is a wasteful number, since it uses less digits than its factorization.

218861649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1198 (or 1192 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 218861649 is about 14793.9734013550. The cubic root of 218861649 is about 602.6380590746.

The spelling of 218861649 in words is "two hundred eighteen million, eight hundred sixty-one thousand, six hundred forty-nine".