217983371505 has 64 divisors (see below), whose sum is σ = 375980901120. Its totient is φ = 107454283776.

The previous prime is 217983371483. The next prime is 217983371509. The reversal of 217983371505 is 505173389712.

It is a de Polignac number, because none of the positive numbers 2^k-217983371505 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (217983371509) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3106134 + ... + 3175536.

It is an arithmetic number, because the mean of its divisors is an integer number (5874701580).

Almost surely, 2^217983371505 is an apocalyptic number.

It is an amenable number.

217983371505 is a deficient number, since it is larger than the sum of its proper divisors (157997529615).

217983371505 is a wasteful number, since it uses less digits than its factorization.

217983371505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69650.

The product of its (nonzero) digits is 1587600, while the sum is 51.

The spelling of 217983371505 in words is "two hundred seventeen billion, nine hundred eighty-three million, three hundred seventy-one thousand, five hundred five".