9987654321 has 16 divisors (see below), whose sum is σ = 14812662400. Its totient is φ = 6651174384.

The previous prime is 9987654263. The next prime is 9987654329. The reversal of 9987654321 is 1234567899.

9987654321 is a `hidden beast` number, since 9 + 9 + 8 + 76 + 543 + 21 = 666.

It is not a de Polignac number, because 9987654321 - 2¹⁴ = 9987637937 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (9987654329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176446 + ... + 226071.

It is an arithmetic number, because the mean of its divisors is an integer number (925791400).

Almost surely, 2^9987654321 is an apocalyptic number.

It is an amenable number.

9987654321 is a deficient number, since it is larger than the sum of its proper divisors (4825008079).

9987654321 is a wasteful number, since it uses less digits than its factorization.

9987654321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403445 (or 403439 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 54.

The square root of 9987654321 is about 99938.2525412567. The cubic root of 9987654321 is about 2153.5477262890.

The spelling of 9987654321 in words is "nine billion, nine hundred eighty-seven million, six hundred fifty-four thousand, three hundred twenty-one".