135521028 has 54 divisors (see below), whose sum is σ = 347864426. Its totient is φ = 44481024.

The previous prime is 135521027. The next prime is 135521039. The reversal of 135521028 is 820125531.

It is a happy number.

135521028 is a `hidden beast` number, since 1 + 3 + 552 + 102 + 8 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 97180164 + 38340864 = 9858^2 + 6192^2 .

It is a junction number, because it is equal to n+sod(n) for n = 135520992 and 135521010.

It is not an unprimeable number, because it can be changed into a prime (135521021) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 687826 + ... + 688022.

Almost surely, 2^135521028 is an apocalyptic number.

135521028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

135521028 is an abundant number, since it is smaller than the sum of its proper divisors (212343398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

135521028 is a wasteful number, since it uses less digits than its factorization.

135521028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 135521028 is about 11641.3499217230. The cubic root of 135521028 is about 513.6518963049.

Adding to 135521028 its reverse (820125531), we get a palindrome (955646559).

The spelling of 135521028 in words is "one hundred thirty-five million, five hundred twenty-one thousand, twenty-eight".