1987638839 has 2 divisors, whose sum is σ = 1987638840. Its totient is φ = 1987638838.

The previous prime is 1987638833. The next prime is 1987638889. The reversal of 1987638839 is 9388367891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1987638839 - 2¹² = 1987634743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1987638833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993819419 + 993819420.

It is an arithmetic number, because the mean of its divisors is an integer number (993819420).

Almost surely, 2^1987638839 is an apocalyptic number.

1987638839 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987638839 is an equidigital number, since it uses as much as digits as its factorization.

1987638839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15676416, while the sum is 62.

The square root of 1987638839 is about 44582.9433640266. The cubic root of 1987638839 is about 1257.3200026941.

The spelling of 1987638839 in words is "one billion, nine hundred eighty-seven million, six hundred thirty-eight thousand, eight hundred thirty-nine".