642645 has 12 divisors (see below), whose sum is σ = 1113996. Its totient is φ = 342720.

The previous prime is 642623. The next prime is 642673. The reversal of 642645 is 546246.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 66564 + 576081 = 258^2 + 759^2 .

It is not a de Polignac number, because 642645 - 2⁵ = 642613 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 7096 + ... + 7185.

It is an arithmetic number, because the mean of its divisors is an integer number (92833).

2⁶⁴²⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

642645 is a deficient number, since it is larger than the sum of its proper divisors (471351).

642645 is a wasteful number, since it uses less digits than its factorization.

642645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14292 (or 14289 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 642645 is about 801.6514205064. The cubic root of 642645 is about 86.2959427571.

The spelling of 642645 in words is "six hundred forty-two thousand, six hundred forty-five".