135123521355 has 16 divisors (see below), whose sum is σ = 240219593760. Its totient is φ = 72065877984.

The previous prime is 135123521303. The next prime is 135123521369. The reversal of 135123521355 is 553125321531.

135123521355 is a `hidden beast` number, since 1 + 3 + 5 + 123 + 521 + 3 + 5 + 5 = 666.

It is not a de Polignac number, because 135123521355 - 2²⁷ = 134989303627 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 500457352 + ... + 500457621.

It is an arithmetic number, because the mean of its divisors is an integer number (15013724610).

Almost surely, 2^135123521355 is an apocalyptic number.

135123521355 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

135123521355 is a deficient number, since it is larger than the sum of its proper divisors (105096072405).

135123521355 is a wasteful number, since it uses less digits than its factorization.

135123521355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000914987 (or 1000914981 counting only the distinct ones).

The product of its digits is 67500, while the sum is 36.

Adding to 135123521355 its reverse (553125321531), we get a palindrome (688248842886).

The spelling of 135123521355 in words is "one hundred thirty-five billion, one hundred twenty-three million, five hundred twenty-one thousand, three hundred fifty-five".