638055139 has 2 divisors, whose sum is σ = 638055140. Its totient is φ = 638055138.

The previous prime is 638055109. The next prime is 638055241. The reversal of 638055139 is 931550836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638055139 - 2¹³ = 638046947 is a prime.

It is a super-2 number, since 2×638055139² = 814228720808618642, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (638055109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319027569 + 319027570.

It is an arithmetic number, because the mean of its divisors is an integer number (319027570).

Almost surely, 2^638055139 is an apocalyptic number.

638055139 is a deficient number, since it is larger than the sum of its proper divisors (1).

638055139 is an equidigital number, since it uses as much as digits as its factorization.

638055139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 97200, while the sum is 40.

The square root of 638055139 is about 25259.7533440056. The cubic root of 638055139 is about 860.9000577801.

The spelling of 638055139 in words is "six hundred thirty-eight million, fifty-five thousand, one hundred thirty-nine".