987878789 has 4 divisors (see below), whose sum is σ = 1045989324. Its totient is φ = 929768256.

The previous prime is 987878779. The next prime is 987878797.

It is a happy number.

987878789 is nontrivially palindromic in base 10.

987878789 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.

It can be written as a sum of positive squares in 2 ways, for example, as 290020900 + 697857889 = 17030^2 + 26417^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-987878789 is a prime.

It is a super-2 number, since 2×987878789² = 1951809003512213042, which contains 22 as substring.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987878719) 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, 29055242 + ... + 29055275.

It is an arithmetic number, because the mean of its divisors is an integer number (261497331).

Almost surely, 2^987878789 is an apocalyptic number.

It is an amenable number.

987878789 is a deficient number, since it is larger than the sum of its proper divisors (58110535).

987878789 is a wasteful number, since it uses less digits than its factorization.

987878789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58110534.

The product of its digits is 113799168, while the sum is 71.

The square root of 987878789 is about 31430.5391140528. The cubic root of 987878789 is about 995.9431606435.

The spelling of 987878789 in words is "nine hundred eighty-seven million, eight hundred seventy-eight thousand, seven hundred eighty-nine".