128751531 has 4 divisors (see below), whose sum is σ = 171668712. Its totient is φ = 85834352.

The previous prime is 128751529. The next prime is 128751533. The reversal of 128751531 is 135157821.

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

It is an interprime number because it is at equal distance from previous prime (128751529) and next prime (128751533).

It is a cyclic number.

It is not a de Polignac number, because 128751531 - 2¹ = 128751529 is a prime.

It is a super-2 number, since 2×128751531² = 33153913469687922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 128751492 and 128751501.

It is not an unprimeable number, because it can be changed into a prime (128751533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21458586 + ... + 21458591.

It is an arithmetic number, because the mean of its divisors is an integer number (42917178).

Almost surely, 2^128751531 is an apocalyptic number.

128751531 is a deficient number, since it is larger than the sum of its proper divisors (42917181).

128751531 is an equidigital number, since it uses as much as digits as its factorization.

128751531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42917180.

The product of its digits is 8400, while the sum is 33.

The square root of 128751531 is about 11346.8731816303. The cubic root of 128751531 is about 504.9528185179.

The spelling of 128751531 in words is "one hundred twenty-eight million, seven hundred fifty-one thousand, five hundred thirty-one".