642642829 has 2 divisors, whose sum is σ = 642642830. Its totient is φ = 642642828.

The previous prime is 642642827. The next prime is 642642851. The reversal of 642642829 is 928246246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 479697604 + 162945225 = 21902^2 + 12765^2 .

It is a cyclic number.

It is not a de Polignac number, because 642642829 - 2¹ = 642642827 is a prime.

Together with 642642827, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642642821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321321414 + 321321415.

It is an arithmetic number, because the mean of its divisors is an integer number (321321415).

Almost surely, 2^642642829 is an apocalyptic number.

It is an amenable number.

642642829 is a deficient number, since it is larger than the sum of its proper divisors (1).

642642829 is an equidigital number, since it uses as much as digits as its factorization.

642642829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 331776, while the sum is 43.

The square root of 642642829 is about 25350.4009632984. The cubic root of 642642829 is about 862.9584558128.

The spelling of 642642829 in words is "six hundred forty-two million, six hundred forty-two thousand, eight hundred twenty-nine".