128749281 has 8 divisors (see below), whose sum is σ = 171847104. Its totient is φ = 85742160.

The previous prime is 128749259. The next prime is 128749303. The reversal of 128749281 is 182947821.

It is an interprime number because it is at equal distance from previous prime (128749259) and next prime (128749303).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128749281 - 2¹¹ = 128747233 is a prime.

It is a super-2 number, since 2×128749281² = 33152754716033922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128749781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19290 + ... + 25091.

It is an arithmetic number, because the mean of its divisors is an integer number (21480888).

Almost surely, 2^128749281 is an apocalyptic number.

It is an amenable number.

128749281 is a deficient number, since it is larger than the sum of its proper divisors (43097823).

128749281 is an equidigital number, since it uses as much as digits as its factorization.

128749281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45351.

The product of its digits is 64512, while the sum is 42.

The square root of 128749281 is about 11346.7740349405. The cubic root of 128749281 is about 504.9498770630.

It can be divided in two parts, 12874 and 9281, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 128749281 in words is "one hundred twenty-eight million, seven hundred forty-nine thousand, two hundred eighty-one".