123515782728 has 128 divisors (see below), whose sum is σ = 343495864320. Its totient is φ = 36754663680.

The previous prime is 123515782723. The next prime is 123515782739. The reversal of 123515782728 is 827287515321.

123515782728 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×123515782728² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (123515782723) 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, 19215051 + ... + 19221477.

It is an arithmetic number, because the mean of its divisors is an integer number (2683561440).

Almost surely, 2^123515782728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 123515782728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171747932160).

123515782728 is an abundant number, since it is smaller than the sum of its proper divisors (219980081592).

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

123515782728 is a wasteful number, since it uses less digits than its factorization.

123515782728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8467 (or 8463 counting only the distinct ones).

The product of its digits is 1881600, while the sum is 51.

The spelling of 123515782728 in words is "one hundred twenty-three billion, five hundred fifteen million, seven hundred eighty-two thousand, seven hundred twenty-eight".