217912680 has 256 divisors, whose sum is σ = 765158400. Its totient is φ = 55800576.

The previous prime is 217912661. The next prime is 217912687. The reversal of 217912680 is 86219712.

It is a super-2 number, since 2×217912680² = 94971872209564800, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (217912687) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4111534 + ... + 4111586.

It is an arithmetic number, because the mean of its divisors is an integer number (2988900).

Almost surely, 2^217912680 is an apocalyptic number.

217912680 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 217912680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (382579200).

217912680 is an abundant number, since it is smaller than the sum of its proper divisors (547245720).

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

217912680 is an equidigital number, since it uses as much as digits as its factorization.

217912680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 217912680 is about 14761.8657357395. The cubic root of 217912680 is about 601.7657981634.

The spelling of 217912680 in words is "two hundred seventeen million, nine hundred twelve thousand, six hundred eighty".