128551331 has 4 divisors (see below), whose sum is σ = 136113192. Its totient is φ = 120989472.

The previous prime is 128551309. The next prime is 128551337. The reversal of 128551331 is 133155821.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 128551331 - 2²⁶ = 61442467 is a prime.

It is a super-2 number, since 2×128551331² = 33050889403743122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 128551294 and 128551303.

It is not an unprimeable number, because it can be changed into a prime (128551337) 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, 3780905 + ... + 3780938.

It is an arithmetic number, because the mean of its divisors is an integer number (34028298).

Almost surely, 2^128551331 is an apocalyptic number.

128551331 is a deficient number, since it is larger than the sum of its proper divisors (7561861).

128551331 is an equidigital number, since it uses as much as digits as its factorization.

128551331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7561860.

The product of its digits is 3600, while the sum is 29.

The square root of 128551331 is about 11338.0479360426. The cubic root of 128551331 is about 504.6909601523.

The spelling of 128551331 in words is "one hundred twenty-eight million, five hundred fifty-one thousand, three hundred thirty-one".