123428505 has 16 divisors (see below), whose sum is σ = 199405440. Its totient is φ = 65188608.

The previous prime is 123428479. The next prime is 123428509. The reversal of 123428505 is 505824321.

It is not a de Polignac number, because 123428505 - 2⁶ = 123428441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (123428509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38400 + ... + 41489.

It is an arithmetic number, because the mean of its divisors is an integer number (12462840).

Almost surely, 2^123428505 is an apocalyptic number.

123428505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

123428505 is a deficient number, since it is larger than the sum of its proper divisors (75976935).

123428505 is a wasteful number, since it uses less digits than its factorization.

123428505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80000.

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 123428505 is about 11109.8382076428. The cubic root of 123428505 is about 497.8958306981.

The spelling of 123428505 in words is "one hundred twenty-three million, four hundred twenty-eight thousand, five hundred five".