128155991111 has 4 divisors (see below), whose sum is σ = 128332272432. Its totient is φ = 127979709792.

The previous prime is 128155991083. The next prime is 128155991113. The reversal of 128155991111 is 111199551821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 111199551821 = 941 ⋅118171681.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128155991111 is a prime.

It is a super-2 number, since 2×128155991111² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128155991113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88139570 + ... + 88141023.

It is an arithmetic number, because the mean of its divisors is an integer number (32083068108).

Almost surely, 2^128155991111 is an apocalyptic number.

128155991111 is a deficient number, since it is larger than the sum of its proper divisors (176281321).

128155991111 is an equidigital number, since it uses as much as digits as its factorization.

128155991111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176281320.

The product of its digits is 32400, while the sum is 44.

The spelling of 128155991111 in words is "one hundred twenty-eight billion, one hundred fifty-five million, nine hundred ninety-one thousand, one hundred eleven".