638775077 has 2 divisors, whose sum is σ = 638775078. Its totient is φ = 638775076.

The previous prime is 638775047. The next prime is 638775097. The reversal of 638775077 is 770577836.

638775077 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 25274²+1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 638775076 + 1 = 25274^2 + 1^2 .

It is a cyclic number.

It is not a de Polignac number, because 638775077 - 2¹⁴ = 638758693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638775037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319387538 + 319387539.

It is an arithmetic number, because the mean of its divisors is an integer number (319387539).

Almost surely, 2^638775077 is an apocalyptic number.

It is an amenable number.

638775077 is a deficient number, since it is larger than the sum of its proper divisors (1).

638775077 is an equidigital number, since it uses as much as digits as its factorization.

638775077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728720, while the sum is 50.

The square root of 638775077 is about 25274.0000197832. Note that the first 4 decimals coincide. The cubic root of 638775077 is about 861.2237297548.

The spelling of 638775077 in words is "six hundred thirty-eight million, seven hundred seventy-five thousand, seventy-seven".