217821996000 has 576 divisors, whose sum is σ = 912018272256. Its totient is φ = 48180096000.

The previous prime is 217821995999. The next prime is 217821996037. The reversal of 217821996000 is 699128712.

217821996000 is a `hidden beast` number, since 2 + 17 + 8 + 21 + 9 + 9 + 600 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7798059 + ... + 7825941.

It is an arithmetic number, because the mean of its divisors is an integer number (1583365056).

Almost surely, 2^217821996000 is an apocalyptic number.

217821996000 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 217821996000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (456009136128).

217821996000 is an abundant number, since it is smaller than the sum of its proper divisors (694196276256).

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

217821996000 is a wasteful number, since it uses less digits than its factorization.

217821996000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27952 (or 27931 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The spelling of 217821996000 in words is "two hundred seventeen billion, eight hundred twenty-one million, nine hundred ninety-six thousand".