218875172985 has 72 divisors (see below), whose sum is σ = 449650922760. Its totient is φ = 98169297408.

The previous prime is 218875172983. The next prime is 218875173001. The reversal of 218875172985 is 589271578812.

218875172985 is a `hidden beast` number, since 2 + 18 + 8 + 7 + 517 + 29 + 85 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 88273163664 + 130602009321 = 297108^2 + 361389^2 .

It is not a de Polignac number, because 218875172985 - 2¹ = 218875172983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (218875172983) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 819580 + ... + 1053309.

It is an arithmetic number, because the mean of its divisors is an integer number (6245151705).

Almost surely, 2^218875172985 is an apocalyptic number.

It is an amenable number.

218875172985 is an abundant number, since it is smaller than the sum of its proper divisors (230775749775).

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

218875172985 is a wasteful number, since it uses less digits than its factorization.

218875172985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1872967 (or 1872957 counting only the distinct ones).

The product of its digits is 22579200, while the sum is 63.

The spelling of 218875172985 in words is "two hundred eighteen billion, eight hundred seventy-five million, one hundred seventy-two thousand, nine hundred eighty-five".