128156331 has 4 divisors (see below), whose sum is σ = 170875112. Its totient is φ = 85437552.

The previous prime is 128156317. The next prime is 128156339. The reversal of 128156331 is 133651821.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-128156331 is a prime.

It is a super-2 number, since 2×128156331² = 32848090350763122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128156339) 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, 21359386 + ... + 21359391.

It is an arithmetic number, because the mean of its divisors is an integer number (42718778).

Almost surely, 2^128156331 is an apocalyptic number.

128156331 is a deficient number, since it is larger than the sum of its proper divisors (42718781).

128156331 is an equidigital number, since it uses as much as digits as its factorization.

128156331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42718780.

The product of its digits is 4320, while the sum is 30.

The square root of 128156331 is about 11320.6153101322. The cubic root of 128156331 is about 504.1735080677.

The spelling of 128156331 in words is "one hundred twenty-eight million, one hundred fifty-six thousand, three hundred thirty-one".