217842138 has 24 divisors (see below), whose sum is σ = 472343508. Its totient is φ = 72559872.

The previous prime is 217842109. The next prime is 217842151. The reversal of 217842138 is 831248712.

217842138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 169442289 + 48399849 = 13017^2 + 6957^2 .

It is a super-2 number, since 2×217842138² = 94910394176822088, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25770 + ... + 33162.

Almost surely, 2^217842138 is an apocalyptic number.

217842138 is an abundant number, since it is smaller than the sum of its proper divisors (254501370).

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

217842138 is a wasteful number, since it uses less digits than its factorization.

217842138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9038 (or 9035 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 217842138 is about 14759.4762102183. The cubic root of 217842138 is about 601.7008572517.

The spelling of 217842138 in words is "two hundred seventeen million, eight hundred forty-two thousand, one hundred thirty-eight".