217828080 has 240 divisors, whose sum is σ = 770200704. Its totient is φ = 55111680.

The previous prime is 217828057. The next prime is 217828087. The reversal of 217828080 is 80828712.

It is a Cunningham number, because it is equal to 14759²-1.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217828087) 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 47 ways as a sum of consecutive naturals, for example, 1387362 + ... + 1387518.

Almost surely, 2^217828080 is an apocalyptic number.

217828080 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 217828080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (385100352).

217828080 is an abundant number, since it is smaller than the sum of its proper divisors (552372624).

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

217828080 is a wasteful number, since it uses less digits than its factorization.

217828080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 217828080 is about 14758.9999661224. Note that the first 4 decimals coincide. The cubic root of 217828080 is about 601.6879137923.

The spelling of 217828080 in words is "two hundred seventeen million, eight hundred twenty-eight thousand, eighty".