217345920 has 256 divisors, whose sum is σ = 777288960. Its totient is φ = 51200000.

The previous prime is 217345897. The next prime is 217345939. The reversal of 217345920 is 29543712.

217345920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 865795 + ... + 866045.

It is an arithmetic number, because the mean of its divisors is an integer number (3036285).

Almost surely, 2^217345920 is an apocalyptic number.

217345920 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 217345920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (388644480).

217345920 is an abundant number, since it is smaller than the sum of its proper divisors (559943040).

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

217345920 is a wasteful number, since it uses less digits than its factorization.

217345920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325 (or 313 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 217345920 is about 14742.6564770397. The cubic root of 217345920 is about 601.2436426960.

The spelling of 217345920 in words is "two hundred seventeen million, three hundred forty-five thousand, nine hundred twenty".