128172361 has 2 divisors, whose sum is σ = 128172362. Its totient is φ = 128172360.

The previous prime is 128172349. The next prime is 128172389. The reversal of 128172361 is 163271821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106605625 + 21566736 = 10325^2 + 4644^2 .

It is a cyclic number.

It is not a de Polignac number, because 128172361 - 2²³ = 119783753 is a prime.

It is not a weakly prime, because it can be changed into another prime (128172301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64086180 + 64086181.

It is an arithmetic number, because the mean of its divisors is an integer number (64086181).

Almost surely, 2^128172361 is an apocalyptic number.

It is an amenable number.

128172361 is a deficient number, since it is larger than the sum of its proper divisors (1).

128172361 is an equidigital number, since it uses as much as digits as its factorization.

128172361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 31.

The square root of 128172361 is about 11321.3232883793. The cubic root of 128172361 is about 504.1945281357.

The spelling of 128172361 in words is "one hundred twenty-eight million, one hundred seventy-two thousand, three hundred sixty-one".