218508642 has 24 divisors (see below), whose sum is σ = 516475440. Its totient is φ = 66214680.

The previous prime is 218508623. The next prime is 218508673. The reversal of 218508642 is 246805812.

218508642 is a `hidden beast` number, since 2 + 1 + 8 + 5 + 0 + 8 + 642 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 218508597 and 218508606.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 551592 + ... + 551987.

It is an arithmetic number, because the mean of its divisors is an integer number (21519810).

Almost surely, 2^218508642 is an apocalyptic number.

218508642 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

218508642 is an abundant number, since it is smaller than the sum of its proper divisors (297966798).

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

218508642 is a wasteful number, since it uses less digits than its factorization.

218508642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1103598 (or 1103595 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 218508642 is about 14782.0378162147. The cubic root of 218508642 is about 602.3138817809.

The spelling of 218508642 in words is "two hundred eighteen million, five hundred eight thousand, six hundred forty-two".