642405 has 16 divisors (see below), whose sum is σ = 1039680. Its totient is φ = 338688.

The previous prime is 642403. The next prime is 642407. The reversal of 642405 is 504246.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (642403) and next prime (642407).

It is not a de Polignac number, because 642405 - 2¹ = 642403 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642405.

It is not an unprimeable number, because it can be changed into a prime (642403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1506 + ... + 1884.

It is an arithmetic number, because the mean of its divisors is an integer number (64980).

2⁶⁴²⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

642405 is a deficient number, since it is larger than the sum of its proper divisors (397275).

642405 is a wasteful number, since it uses less digits than its factorization.

642405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 642405 is about 801.5017155315. The cubic root of 642405 is about 86.2851988238.

The spelling of 642405 in words is "six hundred forty-two thousand, four hundred five".