9871987639 has 4 divisors (see below), whose sum is σ = 9872280856. Its totient is φ = 9871694424.

The previous prime is 9871987613. The next prime is 9871987661. The reversal of 9871987639 is 9367891789.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9871987639 - 2¹⁷ = 9871856567 is a prime.

It is a super-2 number, since 2×9871987639² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9871987039) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88404 + ... + 166009.

It is an arithmetic number, because the mean of its divisors is an integer number (2468070214).

Almost surely, 2^9871987639 is an apocalyptic number.

9871987639 is a deficient number, since it is larger than the sum of its proper divisors (293217).

9871987639 is a wasteful number, since it uses less digits than its factorization.

9871987639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293216.

The product of its digits is 41150592, while the sum is 67.

The square root of 9871987639 is about 99357.8765825840. The cubic root of 9871987639 is about 2145.2020384094.

The spelling of 9871987639 in words is "nine billion, eight hundred seventy-one million, nine hundred eighty-seven thousand, six hundred thirty-nine".