128738581 has 2 divisors, whose sum is σ = 128738582. Its totient is φ = 128738580.

The previous prime is 128738563. The next prime is 128738611. The reversal of 128738581 is 185837821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111640356 + 17098225 = 10566^2 + 4135^2 .

It is a cyclic number.

It is not a de Polignac number, because 128738581 - 2⁹ = 128738069 is a prime.

It is a super-2 number, since 2×128738581² = 33147244475787122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128738551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64369290 + 64369291.

It is an arithmetic number, because the mean of its divisors is an integer number (64369291).

Almost surely, 2^128738581 is an apocalyptic number.

It is an amenable number.

128738581 is a deficient number, since it is larger than the sum of its proper divisors (1).

128738581 is an equidigital number, since it uses as much as digits as its factorization.

128738581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107520, while the sum is 43.

The square root of 128738581 is about 11346.3025254926. The cubic root of 128738581 is about 504.9358883419.

The spelling of 128738581 in words is "one hundred twenty-eight million, seven hundred thirty-eight thousand, five hundred eighty-one".