217920920 has 64 divisors (see below), whose sum is σ = 563328000. Its totient is φ = 74321280.

The previous prime is 217920919. The next prime is 217920959. The reversal of 217920920 is 29029712.

217920920 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53765 + ... + 57675.

It is an arithmetic number, because the mean of its divisors is an integer number (8802000).

Almost surely, 2^217920920 is an apocalyptic number.

217920920 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 217920920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (281664000).

217920920 is an abundant number, since it is smaller than the sum of its proper divisors (345407080).

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

217920920 is a wasteful number, since it uses less digits than its factorization.

217920920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4128 (or 4124 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 217920920 is about 14762.1448306132. The cubic root of 217920920 is about 601.7733829870.

The spelling of 217920920 in words is "two hundred seventeen million, nine hundred twenty thousand, nine hundred twenty".