123456787654321 has 81 divisors (see below), whose sum is σ = 139982237971779. Its totient is φ = 108799998912000.

The previous prime is 123456787654313. The next prime is 123456787654391.

The square root of 123456787654321 is 11111111.

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

123456787654321 is nontrivially palindromic in base 10.

123456787654321 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 13 ways, for example, as 234799362721 + 123221988291600 = 484561^2 + 11100540^2 .

It is not a de Polignac number, because 123456787654321 - 2³ = 123456787654313 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (123456787654391) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 901144435365 + ... + 901144435501.

Almost surely, 2^{123456787654321} is an apocalyptic number.

123456787654321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

123456787654321 is the 11111111-st square number.

123456787654321 is the 5555556-th centered octagonal number.

It is an amenable number.

123456787654321 is a deficient number, since it is larger than the sum of its proper divisors (16525450317458).

123456787654321 is an frugal number, since it uses more digits than its factorization.

123456787654321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644 (or 322 counting only the distinct ones).

The product of its digits is 203212800, while the sum is 64.

It can be divided in two parts, 1234567 and 87654321, that added together give a palindrome (88888888).

The spelling of 123456787654321 in words is "one hundred twenty-three trillion, four hundred fifty-six billion, seven hundred eighty-seven million, six hundred fifty-four thousand, three hundred twenty-one".