128439021744 has 120 divisors (see below), whose sum is σ = 402726469392. Its totient is φ = 37868981760.

The previous prime is 128439021727. The next prime is 128439021749. The reversal of 128439021744 is 447120934821.

128439021744 is a `hidden beast` number, since 1 + 2 + 8 + 4 + 390 + 217 + 44 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 128439021744.

It is not an unprimeable number, because it can be changed into a prime (128439021749) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1037139 + ... + 1154354.

Almost surely, 2^128439021744 is an apocalyptic number.

It is an amenable number.

128439021744 is an abundant number, since it is smaller than the sum of its proper divisors (274287447648).

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

128439021744 is a wasteful number, since it uses less digits than its factorization.

128439021744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2191555 (or 2191546 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The spelling of 128439021744 in words is "one hundred twenty-eight billion, four hundred thirty-nine million, twenty-one thousand, seven hundred forty-four".