217126934640 has 1280 divisors, whose sum is σ = 961447034880. Its totient is φ = 44285875200.

The previous prime is 217126934621. The next prime is 217126934641. The reversal of 217126934640 is 46439621712.

217126934640 is a `hidden beast` number, since 2 + 1 + 7 + 1 + 269 + 346 + 40 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217126934641) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 956506207 + ... + 956506433.

It is an arithmetic number, because the mean of its divisors is an integer number (751130496).

Almost surely, 2^217126934640 is an apocalyptic number.

217126934640 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 217126934640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (480723517440).

217126934640 is an abundant number, since it is smaller than the sum of its proper divisors (744320100240).

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

217126934640 is a wasteful number, since it uses less digits than its factorization.

217126934640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 217126934640 in words is "two hundred seventeen billion, one hundred twenty-six million, nine hundred thirty-four thousand, six hundred forty".