217626828 has 48 divisors (see below), whose sum is σ = 531498240. Its totient is φ = 69175744.

The previous prime is 217626823. The next prime is 217626839. The reversal of 217626828 is 828626712.

It is a happy number.

It is a super-2 number, since 2×217626828² = 94722872530683168, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 217626828.

It is not an unprimeable number, because it can be changed into a prime (217626823) 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, 106351 + ... + 108377.

It is an arithmetic number, because the mean of its divisors is an integer number (11072880).

Almost surely, 2^217626828 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217626828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (265749120).

217626828 is an abundant number, since it is smaller than the sum of its proper divisors (313871412).

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

217626828 is a wasteful number, since it uses less digits than its factorization.

217626828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2446 (or 2444 counting only the distinct ones).

The product of its digits is 129024, while the sum is 42.

The square root of 217626828 is about 14752.1804490048. The cubic root of 217626828 is about 601.5025562889.

The spelling of 217626828 in words is "two hundred seventeen million, six hundred twenty-six thousand, eight hundred twenty-eight".