216658638 has 40 divisors (see below), whose sum is σ = 554832432. Its totient is φ = 61902144.

The previous prime is 216658633. The next prime is 216658661. The reversal of 216658638 is 836856612.

216658638 is a `hidden beast` number, since 2 + 1 + 6 + 6 + 5 + 8 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 216658593 and 216658602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216658633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 94395 + ... + 96662.

Almost surely, 2^216658638 is an apocalyptic number.

216658638 is an abundant number, since it is smaller than the sum of its proper divisors (338173794).

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

216658638 is a wasteful number, since it uses less digits than its factorization.

216658638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191078 (or 191069 counting only the distinct ones).

The product of its digits is 414720, while the sum is 45.

The square root of 216658638 is about 14719.3287211068. The cubic root of 216658638 is about 600.6092311862.

It can be divided in two parts, 21665 and 8638, that added together give a palindrome (30303).

The spelling of 216658638 in words is "two hundred sixteen million, six hundred fifty-eight thousand, six hundred thirty-eight".