217020051187 has 4 divisors (see below), whose sum is σ = 217820863456. Its totient is φ = 216219238920.

The previous prime is 217020051163. The next prime is 217020051211. The reversal of 217020051187 is 781150020712.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (217020051163) and next prime (217020051211).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217020051187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217020052187) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400405728 + ... + 400406269.

It is an arithmetic number, because the mean of its divisors is an integer number (54455215864).

Almost surely, 2^217020051187 is an apocalyptic number.

217020051187 is a deficient number, since it is larger than the sum of its proper divisors (800812269).

217020051187 is an equidigital number, since it uses as much as digits as its factorization.

217020051187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800812268.

The product of its (nonzero) digits is 7840, while the sum is 34.

Adding to 217020051187 its reverse (781150020712), we get a palindrome (998170071899).

The spelling of 217020051187 in words is "two hundred seventeen billion, twenty million, fifty-one thousand, one hundred eighty-seven".