217638680 has 64 divisors (see below), whose sum is σ = 566784000. Its totient is φ = 73666944.

The previous prime is 217638679. The next prime is 217638683. The reversal of 217638680 is 86836712.

It is a happy number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217638683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17201 + ... + 27039.

It is an arithmetic number, because the mean of its divisors is an integer number (8856000).

Almost surely, 2^217638680 is an apocalyptic number.

217638680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217638680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (283392000).

217638680 is an abundant number, since it is smaller than the sum of its proper divisors (349145320).

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

217638680 is a wasteful number, since it uses less digits than its factorization.

217638680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9936 (or 9932 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 217638680 is about 14752.5821468650. The cubic root of 217638680 is about 601.5134754066.

The spelling of 217638680 in words is "two hundred seventeen million, six hundred thirty-eight thousand, six hundred eighty".