123128155 has 4 divisors (see below), whose sum is σ = 147753792. Its totient is φ = 98502520.

The previous prime is 123128149. The next prime is 123128167. The reversal of 123128155 is 551821321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 551821321 = 569 ⋅969809.

It is not a de Polignac number, because 123128155 - 2³ = 123128147 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12312811 + ... + 12312820.

It is an arithmetic number, because the mean of its divisors is an integer number (36938448).

Almost surely, 2^123128155 is an apocalyptic number.

123128155 is a deficient number, since it is larger than the sum of its proper divisors (24625637).

123128155 is an equidigital number, since it uses as much as digits as its factorization.

123128155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24625636.

The product of its digits is 2400, while the sum is 28.

The square root of 123128155 is about 11096.3126758397. The cubic root of 123128155 is about 497.4916440101.

Adding to 123128155 its reverse (551821321), we get a palindrome (674949476).

The spelling of 123128155 in words is "one hundred twenty-three million, one hundred twenty-eight thousand, one hundred fifty-five".