642245 has 4 divisors (see below), whose sum is σ = 770700. Its totient is φ = 513792.

The previous prime is 642241. The next prime is 642247. The reversal of 642245 is 542246.

642245 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 279841 + 362404 = 529^2 + 602^2 .

It is a cyclic number.

It is not a de Polignac number, because 642245 - 2² = 642241 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642245.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642241) 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, 64220 + ... + 64229.

It is an arithmetic number, because the mean of its divisors is an integer number (192675).

2⁶⁴²²⁴⁵ is an apocalyptic number.

It is an amenable number.

642245 is a deficient number, since it is larger than the sum of its proper divisors (128455).

642245 is a wasteful number, since it uses less digits than its factorization.

642245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128454.

The product of its digits is 1920, while the sum is 23.

The square root of 642245 is about 801.4018966786. The cubic root of 642245 is about 86.2780347149.

Subtracting from 642245 its reverse (542246), we obtain a palindrome (99999).

The spelling of 642245 in words is "six hundred forty-two thousand, two hundred forty-five".