987654321 has 18 divisors (see below), whose sum is σ = 1515470502.
Its totient is φ = 619703040.
The previous prime is 987654319. The next prime is 987654323. The reversal of 987654321 is 123456789.
987654321 is a `hidden beast` number, since 9 + 87 + 6 + 543 + 21 = 666.
987654321 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.
It is an interprime number because it is at equal distance from previous prime (987654319) and next prime (987654323).
It can be written as a sum of positive squares in 3 ways, for example, as 654080625 + 333573696 = 25575^2 + 18264^2
It is not a de Polignac number, because 987654321 - 21 = 987654319 is a prime.
It is a super-2 number, since 2×9876543212 = 1950922115579942082, which contains 22 as substring.
It is an alternating number because its digits alternate between odd and even.
It is a straight-line number, since its digits are in arithmetic progression.
It is a nialpdrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (987654323) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is an upside-down number.
It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 187260 + ... + 192461.
Almost surely, 2987654321 is an apocalyptic number.
It is an amenable number.
987654321 is a deficient number, since it is larger than the sum of its proper divisors (527816181).
987654321 is a wasteful number, since it uses less digits than its factorization.
987654321 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 379761 (or 379741 counting only the distinct ones).
The product of its digits is 362880, while the sum is 45.
The square root of 987654321 is about 31426.9680529319.
The cubic root of 987654321 is about 995.8677214613.
The spelling of 987654321 in words is "nine hundred eighty-seven million, six hundred fifty-four thousand, three hundred twenty-one".