217345240 has 32 divisors (see below), whose sum is σ = 558888480. Its totient is φ = 74518272.

The previous prime is 217345231. The next prime is 217345243. The reversal of 217345240 is 42543712.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 217345199 and 217345208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217345243) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 387837 + ... + 388396.

It is an arithmetic number, because the mean of its divisors is an integer number (17465265).

Almost surely, 2^217345240 is an apocalyptic number.

217345240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217345240 is an abundant number, since it is smaller than the sum of its proper divisors (341543240).

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

217345240 is a wasteful number, since it uses less digits than its factorization.

217345240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 776251 (or 776247 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 217345240 is about 14742.6334146922. The cubic root of 217345240 is about 601.2430156677.

Adding to 217345240 its reverse (42543712), we get a palindrome (259888952).

The spelling of 217345240 in words is "two hundred seventeen million, three hundred forty-five thousand, two hundred forty".