642173165 has 4 divisors (see below), whose sum is σ = 770607804. Its totient is φ = 513738528.

The previous prime is 642173131. The next prime is 642173167. The reversal of 642173165 is 561371246.

642173165 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 182628196 + 459544969 = 13514^2 + 21437^2 .

It is a cyclic number.

It is not a de Polignac number, because 642173165 - 2¹⁸ = 641911021 is a prime.

It is a super-2 number, since 2×642173165² = 824772747692234450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642173167) 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, 64217312 + ... + 64217321.

It is an arithmetic number, because the mean of its divisors is an integer number (192651951).

Almost surely, 2^642173165 is an apocalyptic number.

It is an amenable number.

642173165 is a deficient number, since it is larger than the sum of its proper divisors (128434639).

642173165 is a wasteful number, since it uses less digits than its factorization.

642173165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128434638.

The product of its digits is 30240, while the sum is 35.

The square root of 642173165 is about 25341.1358269514. The cubic root of 642173165 is about 862.7481786689.

The spelling of 642173165 in words is "six hundred forty-two million, one hundred seventy-three thousand, one hundred sixty-five".