1238128639 has 16 divisors (see below), whose sum is σ = 1399703040. Its totient is φ = 1084860000.

The previous prime is 1238128609. The next prime is 1238128667. The reversal of 1238128639 is 9368218321.

It is a cyclic number.

It is not a de Polignac number, because 1238128639 - 2¹³ = 1238120447 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1238128595 and 1238128604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1238128609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 198214 + ... + 204364.

It is an arithmetic number, because the mean of its divisors is an integer number (87481440).

Almost surely, 2^1238128639 is an apocalyptic number.

1238128639 is a deficient number, since it is larger than the sum of its proper divisors (161574401).

1238128639 is a wasteful number, since it uses less digits than its factorization.

1238128639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6822.

The product of its digits is 124416, while the sum is 43.

The square root of 1238128639 is about 35187.0521499031. The cubic root of 1238128639 is about 1073.7963492899.

The spelling of 1238128639 in words is "one billion, two hundred thirty-eight million, one hundred twenty-eight thousand, six hundred thirty-nine".