642767 has 4 divisors (see below), whose sum is σ = 644520. Its totient is φ = 641016.

The previous prime is 642739. The next prime is 642769. The reversal of 642767 is 767246.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 767246 = 2 ⋅383623.

It is a cyclic number.

It is not a de Polignac number, because 642767 - 2¹⁸ = 380623 is a prime.

It is a Duffinian number.

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 642767.

It is not an unprimeable number, because it can be changed into a prime (642769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92 + ... + 1137.

It is an arithmetic number, because the mean of its divisors is an integer number (161130).

2⁶⁴²⁷⁶⁷ is an apocalyptic number.

642767 is a deficient number, since it is larger than the sum of its proper divisors (1753).

642767 is a wasteful number, since it uses less digits than its factorization.

642767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1752.

The product of its digits is 14112, while the sum is 32.

The square root of 642767 is about 801.7275098186. The cubic root of 642767 is about 86.3014032311.

The spelling of 642767 in words is "six hundred forty-two thousand, seven hundred sixty-seven".