217215645761640 has 64 divisors (see below), whose sum is σ = 651808999647360. Its totient is φ = 57909766659840.

The previous prime is 217215645761599. The next prime is 217215645761659. The reversal of 217215645761640 is 46167546512712.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 224602084 + ... + 225567123.

It is an arithmetic number, because the mean of its divisors is an integer number (10184515619490).

Almost surely, 2^{217215645761640} is an apocalyptic number.

217215645761640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217215645761640 is an abundant number, since it is smaller than the sum of its proper divisors (434593353885720).

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

217215645761640 is a wasteful number, since it uses less digits than its factorization.

217215645761640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450173242 (or 450173238 counting only the distinct ones).

The product of its (nonzero) digits is 16934400, while the sum is 57.

The spelling of 217215645761640 in words is "two hundred seventeen trillion, two hundred fifteen billion, six hundred forty-five million, seven hundred sixty-one thousand, six hundred forty".