217725648 has 80 divisors (see below), whose sum is σ = 663576576. Its totient is φ = 60197760.

The previous prime is 217725637. The next prime is 217725661. The reversal of 217725648 is 846527712.

217725648 is digitally balanced in base 3, 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 (42).

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, 36 + ... + 20867.

Almost surely, 2^217725648 is an apocalyptic number.

217725648 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 217725648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331788288).

217725648 is an abundant number, since it is smaller than the sum of its proper divisors (445850928).

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

217725648 is a wasteful number, since it uses less digits than its factorization.

217725648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20952 (or 20946 counting only the distinct ones).

The product of its digits is 188160, while the sum is 42.

The square root of 217725648 is about 14755.5294042606. The cubic root of 217725648 is about 601.5935859481.

The spelling of 217725648 in words is "two hundred seventeen million, seven hundred twenty-five thousand, six hundred forty-eight".