642545 has 4 divisors (see below), whose sum is σ = 771060. Its totient is φ = 514032.

The previous prime is 642533. The next prime is 642547. The reversal of 642545 is 545246.

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 364816 + 277729 = 604^2 + 527^2 .

It is a cyclic number.

It is not a de Polignac number, because 642545 - 2⁴ = 642529 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642545.

It is not an unprimeable number, because it can be changed into a prime (642547) 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, 64250 + ... + 64259.

It is an arithmetic number, because the mean of its divisors is an integer number (192765).

2⁶⁴²⁵⁴⁵ is an apocalyptic number.

It is an amenable number.

642545 is a deficient number, since it is larger than the sum of its proper divisors (128515).

642545 is a wasteful number, since it uses less digits than its factorization.

642545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128514.

The product of its digits is 4800, while the sum is 26.

The square root of 642545 is about 801.5890468314. The cubic root of 642545 is about 86.2914664434.

The spelling of 642545 in words is "six hundred forty-two thousand, five hundred forty-five".