217712240640 has 480 divisors, whose sum is σ = 784864080000. Its totient is φ = 57721061376.

The previous prime is 217712240611. The next prime is 217712240657. The reversal of 217712240640 is 46042217712.

217712240640 is a `hidden beast` number, since 2 + 1 + 7 + 7 + 1 + 2 + 2 + 4 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 217712240595 and 217712240604.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 165057901 + ... + 165059219.

It is an arithmetic number, because the mean of its divisors is an integer number (1635133500).

Almost surely, 2^217712240640 is an apocalyptic number.

217712240640 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 217712240640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (392432040000).

217712240640 is an abundant number, since it is smaller than the sum of its proper divisors (567151839360).

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

217712240640 is a wasteful number, since it uses less digits than its factorization.

217712240640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557 (or 1528 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

The spelling of 217712240640 in words is "two hundred seventeen billion, seven hundred twelve million, two hundred forty thousand, six hundred forty".