639346469 has 2 divisors, whose sum is σ = 639346470. Its totient is φ = 639346468.

The previous prime is 639346439. The next prime is 639346493. The reversal of 639346469 is 964643936.

It is a happy number.

639346469 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 616926244 + 22420225 = 24838^2 + 4735^2 .

It is a cyclic number.

It is not a de Polignac number, because 639346469 - 2¹² = 639342373 is a prime.

It is a super-2 number, since 2×639346469² = 817527814845535922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639346439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319673234 + 319673235.

It is an arithmetic number, because the mean of its divisors is an integer number (319673235).

Almost surely, 2^639346469 is an apocalyptic number.

It is an amenable number.

639346469 is a deficient number, since it is larger than the sum of its proper divisors (1).

639346469 is an equidigital number, since it uses as much as digits as its factorization.

639346469 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2519424, while the sum is 50.

The square root of 639346469 is about 25285.3014417467. The cubic root of 639346469 is about 861.4804448915.

The spelling of 639346469 in words is "six hundred thirty-nine million, three hundred forty-six thousand, four hundred sixty-nine".