638523877 has 2 divisors, whose sum is σ = 638523878. Its totient is φ = 638523876.

The previous prime is 638523871. The next prime is 638523881. The reversal of 638523877 is 778325836.

638523877 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., 463067361 + 175456516 = 21519^2 + 13246^2 .

It is a cyclic number.

It is not a de Polignac number, because 638523877 - 2²³ = 630135269 is a prime.

It is a super-2 number, since 2×638523877² = 815425482998222258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 638523877.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638523871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319261938 + 319261939.

It is an arithmetic number, because the mean of its divisors is an integer number (319261939).

Almost surely, 2^638523877 is an apocalyptic number.

It is an amenable number.

638523877 is a deficient number, since it is larger than the sum of its proper divisors (1).

638523877 is an equidigital number, since it uses as much as digits as its factorization.

638523877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1693440, while the sum is 49.

The square root of 638523877 is about 25269.0299972120. The cubic root of 638523877 is about 861.1108221114.

The spelling of 638523877 in words is "six hundred thirty-eight million, five hundred twenty-three thousand, eight hundred seventy-seven".