217394139 has 4 divisors (see below), whose sum is σ = 289858856. Its totient is φ = 144929424.

The previous prime is 217394131. The next prime is 217394141. The reversal of 217394139 is 931493712.

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

It is not a de Polignac number, because 217394139 - 2³ = 217394131 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 217394097 and 217394106.

It is not an unprimeable number, because it can be changed into a prime (217394131) 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, 36232354 + ... + 36232359.

It is an arithmetic number, because the mean of its divisors is an integer number (72464714).

Almost surely, 2^217394139 is an apocalyptic number.

217394139 is a deficient number, since it is larger than the sum of its proper divisors (72464717).

217394139 is an equidigital number, since it uses as much as digits as its factorization.

217394139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72464716.

The product of its digits is 40824, while the sum is 39.

The square root of 217394139 is about 14744.2917429085. The cubic root of 217394139 is about 601.2881021204.

It can be divided in two parts, 21739 and 4139, that added together give a triangular number (25878 = T₂₂₇).

The spelling of 217394139 in words is "two hundred seventeen million, three hundred ninety-four thousand, one hundred thirty-nine".