1938688639 has 2 divisors, whose sum is σ = 1938688640. Its totient is φ = 1938688638.

The previous prime is 1938688627. The next prime is 1938688651. The reversal of 1938688639 is 9368868391.

It is a balanced prime because it is at equal distance from previous prime (1938688627) and next prime (1938688651).

It is a cyclic number.

It is not a de Polignac number, because 1938688639 - 2²¹ = 1936591487 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1938688039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 969344319 + 969344320.

It is an arithmetic number, because the mean of its divisors is an integer number (969344320).

Almost surely, 2^1938688639 is an apocalyptic number.

1938688639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1938688639 is an equidigital number, since it uses as much as digits as its factorization.

1938688639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13436928, while the sum is 61.

The square root of 1938688639 is about 44030.5421156724. The cubic root of 1938688639 is about 1246.9126237511.

The spelling of 1938688639 in words is "one billion, nine hundred thirty-eight million, six hundred eighty-eight thousand, six hundred thirty-nine".