217998001836 has 120 divisors (see below), whose sum is σ = 600895680000. Its totient is φ = 68725384416.

The previous prime is 217998001831. The next prime is 217998001849. The reversal of 217998001836 is 638100899712.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (217998001831) 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 39 ways as a sum of consecutive naturals, for example, 3657885 + ... + 3717003.

It is an arithmetic number, because the mean of its divisors is an integer number (5007464000).

Almost surely, 2^217998001836 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 217998001836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (300447840000).

217998001836 is an abundant number, since it is smaller than the sum of its proper divisors (382897678164).

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

217998001836 is a wasteful number, since it uses less digits than its factorization.

217998001836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59753 (or 59742 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The spelling of 217998001836 in words is "two hundred seventeen billion, nine hundred ninety-eight million, one thousand, eight hundred thirty-six".