642440165 has 4 divisors (see below), whose sum is σ = 770928204. Its totient is φ = 513952128.

The previous prime is 642440159. The next prime is 642440231. The reversal of 642440165 is 561044246.

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

It can be written as a sum of positive squares in 2 ways, for example, as 234763684 + 407676481 = 15322^2 + 20191^2 .

It is a cyclic number.

It is not a de Polignac number, because 642440165 - 2¹⁸ = 642178021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 64244012 + ... + 64244021.

It is an arithmetic number, because the mean of its divisors is an integer number (192732051).

Almost surely, 2^642440165 is an apocalyptic number.

It is an amenable number.

642440165 is a deficient number, since it is larger than the sum of its proper divisors (128488039).

642440165 is a wasteful number, since it uses less digits than its factorization.

642440165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128488038.

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 642440165 is about 25346.4033937756. The cubic root of 642440165 is about 862.8677320119.

The spelling of 642440165 in words is "six hundred forty-two million, four hundred forty thousand, one hundred sixty-five".