128631589 has 2 divisors, whose sum is σ = 128631590. Its totient is φ = 128631588.

The previous prime is 128631563. The next prime is 128631599. The reversal of 128631589 is 985136821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125059489 + 3572100 = 11183^2 + 1890^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128631589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128631509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64315794 + 64315795.

It is an arithmetic number, because the mean of its divisors is an integer number (64315795).

Almost surely, 2^128631589 is an apocalyptic number.

It is an amenable number.

128631589 is a deficient number, since it is larger than the sum of its proper divisors (1).

128631589 is an equidigital number, since it uses as much as digits as its factorization.

128631589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680, while the sum is 43.

The square root of 128631589 is about 11341.5867055717. The cubic root of 128631589 is about 504.7959689456.

The spelling of 128631589 in words is "one hundred twenty-eight million, six hundred thirty-one thousand, five hundred eighty-nine".