217831891000 has 128 divisors (see below), whose sum is σ = 514040904000. Its totient is φ = 86397427200.

The previous prime is 217831890977. The next prime is 217831891001. The reversal of 217831891000 is 198138712.

217831891000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217831891001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 130672167 + ... + 130673833.

Almost surely, 2^217831891000 is an apocalyptic number.

217831891000 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 217831891000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257020452000).

217831891000 is an abundant number, since it is smaller than the sum of its proper divisors (296209013000).

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

217831891000 is a wasteful number, since it uses less digits than its factorization.

217831891000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2714 (or 2700 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 40.

The spelling of 217831891000 in words is "two hundred seventeen billion, eight hundred thirty-one million, eight hundred ninety-one thousand".