12345654321 has 243 divisors, whose sum is σ = 25375524993. Its totient is φ = 5759994240.

The previous prime is 12345654311. The next prime is 12345654341.

The square root of 12345654321 is 111111.

It is a perfect power (a square), and thus also a powerful number.

12345654321 is a `hidden beast` number, since 1 + 2 + 34 + 565 + 43 + 21 = 666.

12345654321 is nontrivially palindromic in base 10.

12345654321 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 51279921 + 12294374400 = 7161^2 + 110880^2 .

It is not a de Polignac number, because 12345654321 - 2⁵ = 12345654289 is a prime.

It is a super-2 number, since 2×12345654321² (a number of 21 digits) contains 22 as substring.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12345654311) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 333666315 + ... + 333666351.

Almost surely, 2^12345654321 is an apocalyptic number.

12345654321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

12345654321 is the 111111-st square number.

12345654321 is the 55556-th centered octagonal number.

It is an amenable number.

12345654321 is an abundant number, since it is smaller than the sum of its proper divisors (13029870672).

12345654321 is a wasteful number, since it uses less digits than its factorization.

12345654321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 71 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

Multiplying 12345654321 by its sum of digits (36), we get a square (444443555556 = 666666²).

It can be divided in two parts, 12345 and 654321, that added together give a palindrome (666666).

The spelling of 12345654321 in words is "twelve billion, three hundred forty-five million, six hundred fifty-four thousand, three hundred twenty-one".