216638638 has 8 divisors (see below), whose sum is σ = 328609440. Its totient is φ = 107102160.

The previous prime is 216638621. The next prime is 216638641. The reversal of 216638638 is 836836612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 216638594 and 216638603.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 608358 + ... + 608713.

It is an arithmetic number, because the mean of its divisors is an integer number (41076180).

Almost surely, 2^216638638 is an apocalyptic number.

216638638 is a deficient number, since it is larger than the sum of its proper divisors (111970802).

216638638 is a wasteful number, since it uses less digits than its factorization.

216638638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1217162.

The product of its digits is 248832, while the sum is 43.

The square root of 216638638 is about 14718.6493266196. The cubic root of 216638638 is about 600.5907496487.

It can be divided in two parts, 2166 and 38638, that added together give a palindrome (40804).

The spelling of 216638638 in words is "two hundred sixteen million, six hundred thirty-eight thousand, six hundred thirty-eight".