642406444609 has 16 divisors (see below), whose sum is σ = 671030680320. Its totient is φ = 613840423680.

The previous prime is 642406444607. The next prime is 642406444627. The reversal of 642406444609 is 906444604246.

It is a cyclic number.

It is not a de Polignac number, because 642406444609 - 2¹ = 642406444607 is a prime.

It is a super-3 number, since 3×642406444609³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642406444607) 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 15 ways as a sum of consecutive naturals, for example, 137293332 + ... + 137298010.

It is an arithmetic number, because the mean of its divisors is an integer number (41939417520).

Almost surely, 2^642406444609 is an apocalyptic number.

It is an amenable number.

642406444609 is a deficient number, since it is larger than the sum of its proper divisors (28624235711).

642406444609 is a wasteful number, since it uses less digits than its factorization.

642406444609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9600.

The product of its (nonzero) digits is 3981312, while the sum is 49.

The spelling of 642406444609 in words is "six hundred forty-two billion, four hundred six million, four hundred forty-four thousand, six hundred nine".