842660209 has 4 divisors (see below), whose sum is σ = 843144304. Its totient is φ = 842176116.

The previous prime is 842660191. The next prime is 842660257. The reversal of 842660209 is 902066248.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 842660209 - 2¹⁷ = 842529137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (842660309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239427 + ... + 242920.

It is an arithmetic number, because the mean of its divisors is an integer number (210786076).

Almost surely, 2^842660209 is an apocalyptic number.

It is an amenable number.

842660209 is a deficient number, since it is larger than the sum of its proper divisors (484095).

842660209 is a wasteful number, since it uses less digits than its factorization.

842660209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484094.

The product of its (nonzero) digits is 41472, while the sum is 37.

The square root of 842660209 is about 29028.6101803032. The cubic root of 842660209 is about 944.5337823274.

It can be divided in two parts, 8426 and 60209, that added together give a triangular number (68635 = T₃₇₀).

The spelling of 842660209 in words is "eight hundred forty-two million, six hundred sixty thousand, two hundred nine".