217120320 has 84 divisors (see below), whose sum is σ = 746813340. Its totient is φ = 57897984.

The previous prime is 217120313. The next prime is 217120327. The reversal of 217120320 is 23021712.

217120320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (217120313) and next prime (217120327).

It can be written as a sum of positive squares in 2 ways, for example, as 61968384 + 155151936 = 7872^2 + 12456^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 217120293 and 217120302.

It is not an unprimeable number, because it can be changed into a prime (217120327) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34815 + ... + 40574.

It is an arithmetic number, because the mean of its divisors is an integer number (8890635).

Almost surely, 2^217120320 is an apocalyptic number.

217120320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217120320 is an abundant number, since it is smaller than the sum of its proper divisors (529693020).

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

217120320 is a wasteful number, since it uses less digits than its factorization.

217120320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75412 (or 75399 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 217120320 is about 14735.0032236169. The cubic root of 217120320 is about 601.0355450492.

The spelling of 217120320 in words is "two hundred seventeen million, one hundred twenty thousand, three hundred twenty".