128423778 has 16 divisors (see below), whose sum is σ = 293540160. Its totient is φ = 36692496.

The previous prime is 128423773. The next prime is 128423783. The reversal of 128423778 is 877324821.

It is an interprime number because it is at equal distance from previous prime (128423773) and next prime (128423783).

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 3057709 = 128423778 / (1 + 2 + 8 + 4 + 2 + 3 + 7 + 7 + 8).

It is not an unprimeable number, because it can be changed into a prime (128423773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1528813 + ... + 1528896.

It is an arithmetic number, because the mean of its divisors is an integer number (18346260).

Almost surely, 2^128423778 is an apocalyptic number.

128423778 is an abundant number, since it is smaller than the sum of its proper divisors (165116382).

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

128423778 is a wasteful number, since it uses less digits than its factorization.

128423778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3057721.

The product of its digits is 150528, while the sum is 42.

The square root of 128423778 is about 11332.4215417536. The cubic root of 128423778 is about 504.5239810710.

The spelling of 128423778 in words is "one hundred twenty-eight million, four hundred twenty-three thousand, seven hundred seventy-eight".