135603661 has 2 divisors, whose sum is σ = 135603662. Its totient is φ = 135603660.

The previous prime is 135603659. The next prime is 135603667. The reversal of 135603661 is 166306531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127012900 + 8590761 = 11270^2 + 2931^2 .

It is an emirp because it is prime and its reverse (166306531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 135603661 - 2¹ = 135603659 is a prime.

Together with 135603659, 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 (135603667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67801830 + 67801831.

It is an arithmetic number, because the mean of its divisors is an integer number (67801831).

Almost surely, 2^135603661 is an apocalyptic number.

It is an amenable number.

135603661 is a deficient number, since it is larger than the sum of its proper divisors (1).

135603661 is an equidigital number, since it uses as much as digits as its factorization.

135603661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9720, while the sum is 31.

The square root of 135603661 is about 11644.8984967667. The cubic root of 135603661 is about 513.7562736450.

The spelling of 135603661 in words is "one hundred thirty-five million, six hundred three thousand, six hundred sixty-one".