123309828 has 18 divisors (see below), whose sum is σ = 311699934. Its totient is φ = 41103264.

The previous prime is 123309821. The next prime is 123309833. The reversal of 123309828 is 828903321.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 66879684 + 56430144 = 8178^2 + 7512^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 3425273 = 123309828 / (1 + 2 + 3 + 3 + 0 + 9 + 8 + 2 + 8).

It is a junction number, because it is equal to n+sod(n) for n = 123309792 and 123309801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123309821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1712601 + ... + 1712672.

It is an arithmetic number, because the mean of its divisors is an integer number (17316663).

Almost surely, 2^123309828 is an apocalyptic number.

123309828 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

123309828 is an abundant number, since it is smaller than the sum of its proper divisors (188390106).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

123309828 is a wasteful number, since it uses less digits than its factorization.

123309828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3425283 (or 3425278 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 123309828 is about 11104.4958462778. The cubic root of 123309828 is about 497.7362032505.

The spelling of 123309828 in words is "one hundred twenty-three million, three hundred nine thousand, eight hundred twenty-eight".