987891887137 has 4 divisors (see below), whose sum is σ = 987939427860. Its totient is φ = 987844346416.

The previous prime is 987891887039. The next prime is 987891887149. The reversal of 987891887137 is 731788198789.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 731788198789 = 61 ⋅11996527849.

It can be written as a sum of positive squares in 2 ways, for example, as 741236624401 + 246655262736 = 860951^2 + 496644^2 .

It is a cyclic number.

It is not a de Polignac number, because 987891887137 - 2¹¹ = 987891885089 is a prime.

It is a super-2 number, since 2×987891887137² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (987891887197) 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, 23739178 + ... + 23780755.

It is an arithmetic number, because the mean of its divisors is an integer number (246984856965).

Almost surely, 2^987891887137 is an apocalyptic number.

It is an amenable number.

987891887137 is a deficient number, since it is larger than the sum of its proper divisors (47540723).

987891887137 is a wasteful number, since it uses less digits than its factorization.

987891887137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47540722.

The product of its digits is 341397504, while the sum is 76.

The spelling of 987891887137 in words is "nine hundred eighty-seven billion, eight hundred ninety-one million, eight hundred eighty-seven thousand, one hundred thirty-seven".