123428779905 has 32 divisors (see below), whose sum is σ = 209159501184. Its totient is φ = 61939629056.

The previous prime is 123428779897. The next prime is 123428779909. The reversal of 123428779905 is 509977824321.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 123428779905 - 2³ = 123428779897 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (123428779909) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 906127 + ... + 1033403.

It is an arithmetic number, because the mean of its divisors is an integer number (6536234412).

Almost surely, 2^123428779905 is an apocalyptic number.

123428779905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

123428779905 is a deficient number, since it is larger than the sum of its proper divisors (85730721279).

123428779905 is a wasteful number, since it uses less digits than its factorization.

123428779905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131105.

The product of its (nonzero) digits is 7620480, while the sum is 57.

The spelling of 123428779905 in words is "one hundred twenty-three billion, four hundred twenty-eight million, seven hundred seventy-nine thousand, nine hundred five".