217230640 has 80 divisors (see below), whose sum is σ = 568820736. Its totient is φ = 76435200.

The previous prime is 217230631. The next prime is 217230647. The reversal of 217230640 is 46032712.

217230640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (217230647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23299 + ... + 31261.

Almost surely, 2^217230640 is an apocalyptic number.

217230640 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 217230640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (284410368).

217230640 is an abundant number, since it is smaller than the sum of its proper divisors (351590096).

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

217230640 is a wasteful number, since it uses less digits than its factorization.

217230640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8018 (or 8012 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 217230640 is about 14738.7462153332. The cubic root of 217230640 is about 601.1373242751.

The spelling of 217230640 in words is "two hundred seventeen million, two hundred thirty thousand, six hundred forty".