135601621 has 2 divisors, whose sum is σ = 135601622. Its totient is φ = 135601620.

The previous prime is 135601619. The next prime is 135601643. The reversal of 135601621 is 126106531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115799121 + 19802500 = 10761^2 + 4450^2 .

It is a cyclic number.

It is not a de Polignac number, because 135601621 - 2¹ = 135601619 is a prime.

Together with 135601619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135601321) 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, 67800810 + 67800811.

It is an arithmetic number, because the mean of its divisors is an integer number (67800811).

Almost surely, 2^135601621 is an apocalyptic number.

It is an amenable number.

135601621 is a deficient number, since it is larger than the sum of its proper divisors (1).

135601621 is an equidigital number, since it uses as much as digits as its factorization.

135601621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 135601621 is about 11644.8109044329. The cubic root of 135601621 is about 513.7536973428.

The spelling of 135601621 in words is "one hundred thirty-five million, six hundred one thousand, six hundred twenty-one".