217321830 has 48 divisors (see below), whose sum is σ = 616406544. Its totient is φ = 52683840.

The previous prime is 217321787. The next prime is 217321849. The reversal of 217321830 is 38123712.

It is a junction number, because it is equal to n+sod(n) for n = 217321794 and 217321803.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 108769 + ... + 110748.

It is an arithmetic number, because the mean of its divisors is an integer number (12841803).

Almost surely, 2^217321830 is an apocalyptic number.

217321830 is an abundant number, since it is smaller than the sum of its proper divisors (399084714).

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

217321830 is a wasteful number, since it uses less digits than its factorization.

217321830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219541 (or 219538 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 217321830 is about 14741.8394374651. The cubic root of 217321830 is about 601.2214285001.

The spelling of 217321830 in words is "two hundred seventeen million, three hundred twenty-one thousand, eight hundred thirty".