128891637539 has 16 divisors (see below), whose sum is σ = 147479102400. Its totient is φ = 110347864704.

The previous prime is 128891637509. The next prime is 128891637547. The reversal of 128891637539 is 935736198821.

It is a de Polignac number, because none of the positive numbers 2^k-128891637539 is a prime.

It is a super-2 number, since 2×128891637539² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128891637509) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38030657 + ... + 38034045.

It is an arithmetic number, because the mean of its divisors is an integer number (9217443900).

Almost surely, 2^128891637539 is an apocalyptic number.

128891637539 is a deficient number, since it is larger than the sum of its proper divisors (18587464861).

128891637539 is a wasteful number, since it uses less digits than its factorization.

128891637539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8222.

The product of its digits is 19595520, while the sum is 62.

The spelling of 128891637539 in words is "one hundred twenty-eight billion, eight hundred ninety-one million, six hundred thirty-seven thousand, five hundred thirty-nine".