217080864 has 384 divisors, whose sum is σ = 853493760. Its totient is φ = 51840000.

The previous prime is 217080847. The next prime is 217080869. The reversal of 217080864 is 468080712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (217080869) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 864739 + ... + 864989.

It is an arithmetic number, because the mean of its divisors is an integer number (2222640).

Almost surely, 2^217080864 is an apocalyptic number.

217080864 is a gapful number since it is divisible by the number (24) 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 217080864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (426746880).

217080864 is an abundant number, since it is smaller than the sum of its proper divisors (636412896).

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

217080864 is a wasteful number, since it uses less digits than its factorization.

217080864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 217080864 is about 14733.6643100079. The cubic root of 217080864 is about 600.9991352909. Note that the first 3 decimals are identical.

The spelling of 217080864 in words is "two hundred seventeen million, eighty thousand, eight hundred sixty-four".