639451 has 2 divisors, whose sum is σ = 639452. Its totient is φ = 639450.

The previous prime is 639439. The next prime is 639487. The reversal of 639451 is 154936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639451 - 2¹³ = 631259 is a prime.

639451 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (639491) 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, 319725 + 319726.

It is an arithmetic number, because the mean of its divisors is an integer number (319726).

2⁶³⁹⁴⁵¹ is an apocalyptic number.

639451 is a deficient number, since it is larger than the sum of its proper divisors (1).

639451 is an equidigital number, since it uses as much as digits as its factorization.

639451 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 28.

The square root of 639451 is about 799.6568013842. The cubic root of 639451 is about 86.1527392053.

The spelling of 639451 in words is "six hundred thirty-nine thousand, four hundred fifty-one".