217306540 has 48 divisors (see below), whose sum is σ = 499322880. Its totient is φ = 78783680.

The previous prime is 217306501. The next prime is 217306543. The reversal of 217306540 is 45603712.

217306540 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 217306499 and 217306508.

It is not an unprimeable number, because it can be changed into a prime (217306543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82971 + ... + 85549.

It is an arithmetic number, because the mean of its divisors is an integer number (10402560).

Almost surely, 2^217306540 is an apocalyptic number.

217306540 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 217306540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249661440).

217306540 is an abundant number, since it is smaller than the sum of its proper divisors (282016340).

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

217306540 is a wasteful number, since it uses less digits than its factorization.

217306540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2982 (or 2980 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 217306540 is about 14741.3208363430. The cubic root of 217306540 is about 601.2073282274.

The spelling of 217306540 in words is "two hundred seventeen million, three hundred six thousand, five hundred forty".