217278628 has 48 divisors (see below), whose sum is σ = 451247104. Its totient is φ = 89579520.

The previous prime is 217278619. The next prime is 217278667. The reversal of 217278628 is 826872712.

217278628 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166876 + ... + 168172.

Almost surely, 2^217278628 is an apocalyptic number.

217278628 is a gapful number since it is divisible by the number (28) 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 217278628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (225623552).

217278628 is an abundant number, since it is smaller than the sum of its proper divisors (233968476).

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

217278628 is a wasteful number, since it uses less digits than its factorization.

217278628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1532 (or 1530 counting only the distinct ones).

The product of its digits is 150528, while the sum is 43.

The square root of 217278628 is about 14740.3740793780. The cubic root of 217278628 is about 601.1815863767.

The spelling of 217278628 in words is "two hundred seventeen million, two hundred seventy-eight thousand, six hundred twenty-eight".