642565 has 16 divisors (see below), whose sum is σ = 961920. Its totient is φ = 400320.

The previous prime is 642563. The next prime is 642581. The reversal of 642565 is 565246.

It is not a de Polignac number, because 642565 - 2¹ = 642563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 450 + ... + 1219.

It is an arithmetic number, because the mean of its divisors is an integer number (60120).

2⁶⁴²⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

642565 is a deficient number, since it is larger than the sum of its proper divisors (319355).

642565 is a wasteful number, since it uses less digits than its factorization.

642565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1692.

The product of its digits is 7200, while the sum is 28.

The square root of 642565 is about 801.6015219546. The cubic root of 642565 is about 86.2923617433.

It can be divided in two parts, 64256 and 5, that added together give a triangular number (64261 = T₃₅₈).

The spelling of 642565 in words is "six hundred forty-two thousand, five hundred sixty-five".