989878987 has 4 divisors (see below), whose sum is σ = 989993016. Its totient is φ = 989764960.

The previous prime is 989878979. The next prime is 989878997. The reversal of 989878987 is 789878989.

989878987 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789878989 = 12451 ⋅63439.

It is a cyclic number.

It is not a de Polignac number, because 989878987 - 2³ = 989878979 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (989878997) 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, 42814 + ... + 61747.

It is an arithmetic number, because the mean of its divisors is an integer number (247498254).

Almost surely, 2^989878987 is an apocalyptic number.

989878987 is a deficient number, since it is larger than the sum of its proper divisors (114029).

989878987 is a wasteful number, since it uses less digits than its factorization.

989878987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114028.

The product of its digits is 146313216, while the sum is 73.

The square root of 989878987 is about 31462.3423635304. The cubic root of 989878987 is about 996.6148829123.

The spelling of 989878987 in words is "nine hundred eighty-nine million, eight hundred seventy-eight thousand, nine hundred eighty-seven".