642869 has 2 divisors, whose sum is σ = 642870. Its totient is φ = 642868.

The previous prime is 642853. The next prime is 642871. The reversal of 642869 is 968246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 624100 + 18769 = 790^2 + 137^2 .

It is a cyclic number.

It is not a de Polignac number, because 642869 - 2⁴ = 642853 is a prime.

It is a super-2 number, since 2×642869² = 826561102322, which contains 22 as substring.

Together with 642871, it forms a pair of twin primes.

It is a Chen 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 642869.

It is not a weakly prime, because it can be changed into another prime (642809) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321434 + 321435.

It is an arithmetic number, because the mean of its divisors is an integer number (321435).

2⁶⁴²⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

642869 is a deficient number, since it is larger than the sum of its proper divisors (1).

642869 is an equidigital number, since it uses as much as digits as its factorization.

642869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 35.

The square root of 642869 is about 801.7911199309. The cubic root of 642869 is about 86.3059680151.

It can be divided in two parts, 6 and 42869, that added together give a cube (42875 = 35³).

The spelling of 642869 in words is "six hundred forty-two thousand, eight hundred sixty-nine".