642769 has 2 divisors, whose sum is σ = 642770. Its totient is φ = 642768.

The previous prime is 642739. The next prime is 642779. The reversal of 642769 is 967246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 345744 + 297025 = 588^2 + 545^2 .

It is a cyclic number.

It is not a de Polignac number, because 642769 - 2⁵ = 642737 is a prime.

It is a super-2 number, since 2×642769² = 826303974722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (642739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321384 + 321385.

It is an arithmetic number, because the mean of its divisors is an integer number (321385).

2⁶⁴²⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

642769 is a deficient number, since it is larger than the sum of its proper divisors (1).

642769 is an equidigital number, since it uses as much as digits as its factorization.

642769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 34.

The square root of 642769 is about 801.7287571243. The cubic root of 642769 is about 86.3014927413.

The spelling of 642769 in words is "six hundred forty-two thousand, seven hundred sixty-nine".