217839897 has 12 divisors (see below), whose sum is σ = 343263024. Its totient is φ = 132024120.

The previous prime is 217839889. The next prime is 217839907. The reversal of 217839897 is 798938712.

It is not a de Polignac number, because 217839897 - 2³ = 217839889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (217839497) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1100103 + ... + 1100300.

It is an arithmetic number, because the mean of its divisors is an integer number (28605252).

Almost surely, 2^217839897 is an apocalyptic number.

It is an amenable number.

217839897 is a deficient number, since it is larger than the sum of its proper divisors (125423127).

217839897 is a wasteful number, since it uses less digits than its factorization.

217839897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2200420 (or 2200417 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 54.

The square root of 217839897 is about 14759.4002926948. The cubic root of 217839897 is about 601.6987939591.

The spelling of 217839897 in words is "two hundred seventeen million, eight hundred thirty-nine thousand, eight hundred ninety-seven".