428639 has 2 divisors, whose sum is σ = 428640. Its totient is φ = 428638.

The previous prime is 428633. The next prime is 428657. The reversal of 428639 is 936824.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-428639 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428633) by changing a digit.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214319 + 214320.

It is an arithmetic number, because the mean of its divisors is an integer number (214320).

2⁴²⁸⁶³⁹ is an apocalyptic number.

428639 is a deficient number, since it is larger than the sum of its proper divisors (1).

428639 is an equidigital number, since it uses as much as digits as its factorization.

428639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 32.

The square root of 428639 is about 654.7052772049. The cubic root of 428639 is about 75.3987063173.

The spelling of 428639 in words is "four hundred twenty-eight thousand, six hundred thirty-nine".