128155686501 has 4 divisors (see below), whose sum is σ = 170874248672. Its totient is φ = 85437124332.

The previous prime is 128155686469. The next prime is 128155686539. The reversal of 128155686501 is 105686551821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 105686551821 = 3 ⋅35228850607.

It is not a de Polignac number, because 128155686501 - 2⁵ = 128155686469 is a prime.

It is a super-3 number, since 3×128155686501³ (a number of 34 digits) contains 333 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 (128155686541) 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, 21359281081 + ... + 21359281086.

It is an arithmetic number, because the mean of its divisors is an integer number (42718562168).

Almost surely, 2^128155686501 is an apocalyptic number.

It is an amenable number.

128155686501 is a deficient number, since it is larger than the sum of its proper divisors (42718562171).

128155686501 is an equidigital number, since it uses as much as digits as its factorization.

128155686501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42718562170.

The product of its (nonzero) digits is 576000, while the sum is 48.

The spelling of 128155686501 in words is "one hundred twenty-eight billion, one hundred fifty-five million, six hundred eighty-six thousand, five hundred one".