217087734864 has 1280 divisors, whose sum is σ = 847945728000. Its totient is φ = 46942156800.

The previous prime is 217087734863. The next prime is 217087734911. The reversal of 217087734864 is 468437780712.

It is a super-2 number, since 2×217087734864² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217087734863) 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, 1028851719 + ... + 1028851929.

It is an arithmetic number, because the mean of its divisors is an integer number (662457600).

Almost surely, 2^217087734864 is an apocalyptic number.

217087734864 is a gapful number since it is divisible by the number (24) 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 217087734864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (423972864000).

217087734864 is an abundant number, since it is smaller than the sum of its proper divisors (630857993136).

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

217087734864 is a wasteful number, since it uses less digits than its factorization.

217087734864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 12644352, while the sum is 57.

The spelling of 217087734864 in words is "two hundred seventeen billion, eighty-seven million, seven hundred thirty-four thousand, eight hundred sixty-four".