135721601 has 2 divisors, whose sum is σ = 135721602. Its totient is φ = 135721600.

The previous prime is 135721577. The next prime is 135721609. The reversal of 135721601 is 106127531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120472576 + 15249025 = 10976^2 + 3905^2 .

It is a cyclic number.

It is not a de Polignac number, because 135721601 - 2²⁶ = 68612737 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (135721609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67860800 + 67860801.

It is an arithmetic number, because the mean of its divisors is an integer number (67860801).

Almost surely, 2^135721601 is an apocalyptic number.

It is an amenable number.

135721601 is a deficient number, since it is larger than the sum of its proper divisors (1).

135721601 is an equidigital number, since it uses as much as digits as its factorization.

135721601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1260, while the sum is 26.

The square root of 135721601 is about 11649.9614162451. The cubic root of 135721601 is about 513.9051753693.

The spelling of 135721601 in words is "one hundred thirty-five million, seven hundred twenty-one thousand, six hundred one".