135661553 has 2 divisors, whose sum is σ = 135661554. Its totient is φ = 135661552.

The previous prime is 135661541. The next prime is 135661601. The reversal of 135661553 is 355166531.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 94342369 + 41319184 = 9713^2 + 6428^2 .

It is a cyclic number.

It is not a de Polignac number, because 135661553 - 2⁸ = 135661297 is a prime.

It is not a weakly prime, because it can be changed into another prime (135661523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67830776 + 67830777.

It is an arithmetic number, because the mean of its divisors is an integer number (67830777).

Almost surely, 2^135661553 is an apocalyptic number.

It is an amenable number.

135661553 is a deficient number, since it is larger than the sum of its proper divisors (1).

135661553 is an equidigital number, since it uses as much as digits as its factorization.

135661553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40500, while the sum is 35.

The square root of 135661553 is about 11647.3839552064. The cubic root of 135661553 is about 513.8293742935.

The spelling of 135661553 in words is "one hundred thirty-five million, six hundred sixty-one thousand, five hundred fifty-three".