128138287 has 4 divisors (see below), whose sum is σ = 129893680. Its totient is φ = 126382896.

The previous prime is 128138251. The next prime is 128138303. The reversal of 128138287 is 782831821.

128138287 is nontrivially palindromic in base 8.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 782831821 = 19759 ⋅39619.

It is a cyclic number.

It is not a de Polignac number, because 128138287 - 2¹⁵ = 128105519 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128138207) 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, 877587 + ... + 877732.

It is an arithmetic number, because the mean of its divisors is an integer number (32473420).

Almost surely, 2^128138287 is an apocalyptic number.

128138287 is a deficient number, since it is larger than the sum of its proper divisors (1755393).

128138287 is an equidigital number, since it uses as much as digits as its factorization.

128138287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1755392.

The product of its digits is 43008, while the sum is 40.

The square root of 128138287 is about 11319.8183289309. The cubic root of 128138287 is about 504.1498449532.

The spelling of 128138287 in words is "one hundred twenty-eight million, one hundred thirty-eight thousand, two hundred eighty-seven".