120639 has 4 divisors (see below), whose sum is σ = 160856. Its totient is φ = 80424.

The previous prime is 120623. The next prime is 120641. The reversal of 120639 is 936021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936021 = 3 ⋅312007.

It is not a de Polignac number, because 120639 - 2⁴ = 120623 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120619) 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, 20104 + ... + 20109.

It is an arithmetic number, because the mean of its divisors is an integer number (40214).

2¹²⁰⁶³⁹ is an apocalyptic number.

120639 is a deficient number, since it is larger than the sum of its proper divisors (40217).

120639 is an equidigital number, since it uses as much as digits as its factorization.

120639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40216.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 120639 is about 347.3312539925. The cubic root of 120639 is about 49.4116370712.

The spelling of 120639 in words is "one hundred twenty thousand, six hundred thirty-nine".