639946693 has 2 divisors, whose sum is σ = 639946694. Its totient is φ = 639946692.

The previous prime is 639946651. The next prime is 639946711. The reversal of 639946693 is 396649936.

639946693 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., 367795684 + 272151009 = 19178^2 + 16497^2 .

It is a cyclic number.

It is not a de Polignac number, because 639946693 - 2¹³ = 639938501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639946613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319973346 + 319973347.

It is an arithmetic number, because the mean of its divisors is an integer number (319973347).

Almost surely, 2^639946693 is an apocalyptic number.

It is an amenable number.

639946693 is a deficient number, since it is larger than the sum of its proper divisors (1).

639946693 is an equidigital number, since it uses as much as digits as its factorization.

639946693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5668704, while the sum is 55.

The square root of 639946693 is about 25297.1676873123. The cubic root of 639946693 is about 861.7499490047.

The spelling of 639946693 in words is "six hundred thirty-nine million, nine hundred forty-six thousand, six hundred ninety-three".