217992768 has 336 divisors, whose sum is σ = 750539520. Its totient is φ = 55394304.

The previous prime is 217992767. The next prime is 217992793. The reversal of 217992768 is 867299712.

217992768 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 217992768.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217992767) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4638121 + ... + 4638167.

Almost surely, 2^217992768 is an apocalyptic number.

217992768 is a gapful number since it is divisible by the number (28) 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 217992768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (375269760).

217992768 is an abundant number, since it is smaller than the sum of its proper divisors (532546752).

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

217992768 is a wasteful number, since it uses less digits than its factorization.

217992768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 105 counting only the distinct ones).

The product of its digits is 762048, while the sum is 51.

The square root of 217992768 is about 14764.5781517793. The cubic root of 217992768 is about 601.8395101296.

The spelling of 217992768 in words is "two hundred seventeen million, nine hundred ninety-two thousand, seven hundred sixty-eight".