642765 has 16 divisors (see below), whose sum is σ = 1044288. Its totient is φ = 337536.

The previous prime is 642739. The next prime is 642769. The reversal of 642765 is 567246.

It is not a de Polignac number, because 642765 - 2⁶ = 642701 is a prime.

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 642765.

It is not an unprimeable number, because it can be changed into a prime (642769) 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, 802 + ... + 1388.

It is an arithmetic number, because the mean of its divisors is an integer number (65268).

2⁶⁴²⁷⁶⁵ is an apocalyptic number.

It is an amenable number.

642765 is a deficient number, since it is larger than the sum of its proper divisors (401523).

642765 is a wasteful number, since it uses less digits than its factorization.

642765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 668.

The product of its digits is 10080, while the sum is 30.

The square root of 642765 is about 801.7262625111. The cubic root of 642765 is about 86.3013137207.

The spelling of 642765 in words is "six hundred forty-two thousand, seven hundred sixty-five".