123456789 has 12 divisors (see below), whose sum is σ = 178422816. Its totient is φ = 82260072.

The previous prime is 123456761. The next prime is 123456791. The reversal of 123456789 is 987654321.

123456789 is a `hidden beast` number, since 1 + 2 + 3 + 4 + 567 + 89 = 666.

123456789 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is not a de Polignac number, because 123456789 - 2⁵ = 123456757 is a prime.

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 plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123456719) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30562 + ... + 34364.

It is an arithmetic number, because the mean of its divisors is an integer number (14868568).

Almost surely, 2^123456789 is an apocalyptic number.

It is an amenable number.

123456789 is a deficient number, since it is larger than the sum of its proper divisors (54966027).

123456789 is a wasteful number, since it uses less digits than its factorization.

123456789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7416 (or 7413 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 123456789 is about 11111.1110605556. Note that the first 3 decimals coincide. The cubic root of 123456789 is about 497.9338592182.

The spelling of 123456789 in words is "one hundred twenty-three million, four hundred fifty-six thousand, seven hundred eighty-nine".