217913028 has 12 divisors (see below), whose sum is σ = 508463760. Its totient is φ = 72637672.

The previous prime is 217913023. The next prime is 217913039. The reversal of 217913028 is 820319712.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 217913028.

It is not an unprimeable number, because it can be changed into a prime (217913023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9079698 + ... + 9079721.

It is an arithmetic number, because the mean of its divisors is an integer number (42371980).

Almost surely, 2^217913028 is an apocalyptic number.

It is an amenable number.

217913028 is an abundant number, since it is smaller than the sum of its proper divisors (290550732).

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

217913028 is a wasteful number, since it uses less digits than its factorization.

217913028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18159426 (or 18159424 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 217913028 is about 14761.8775228627. The cubic root of 217913028 is about 601.7661184972.

The spelling of 217913028 in words is "two hundred seventeen million, nine hundred thirteen thousand, twenty-eight".