987428989 has 4 divisors (see below), whose sum is σ = 988233660. Its totient is φ = 986624320.

The previous prime is 987428983. The next prime is 987429011. The reversal of 987428989 is 989824789.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 989824789 = 7963 ⋅124303.

It can be written as a sum of positive squares in 2 ways, for example, as 980316100 + 7112889 = 31310^2 + 2667^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-987428989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 987428989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987428983) 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, 400492 + ... + 402949.

It is an arithmetic number, because the mean of its divisors is an integer number (247058415).

Almost surely, 2^987428989 is an apocalyptic number.

It is an amenable number.

987428989 is a deficient number, since it is larger than the sum of its proper divisors (804671).

987428989 is a wasteful number, since it uses less digits than its factorization.

987428989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804670.

The product of its digits is 20901888, while the sum is 64.

The square root of 987428989 is about 31423.3828382623. The cubic root of 987428989 is about 995.7919804089.

The spelling of 987428989 in words is "nine hundred eighty-seven million, four hundred twenty-eight thousand, nine hundred eighty-nine".