642844109 has 4 divisors (see below), whose sum is σ = 657794016. Its totient is φ = 627894204.

The previous prime is 642844099. The next prime is 642844129. The reversal of 642844109 is 901448246.

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 642844109 - 2¹⁶ = 642778573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642844129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7474889 + ... + 7474974.

It is an arithmetic number, because the mean of its divisors is an integer number (164448504).

Almost surely, 2^642844109 is an apocalyptic number.

It is an amenable number.

642844109 is a deficient number, since it is larger than the sum of its proper divisors (14949907).

642844109 is a wasteful number, since it uses less digits than its factorization.

642844109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14949906.

The product of its (nonzero) digits is 55296, while the sum is 38.

The square root of 642844109 is about 25354.3706094235. The cubic root of 642844109 is about 863.0485411806.

The spelling of 642844109 in words is "six hundred forty-two million, eight hundred forty-four thousand, one hundred nine".