135355211221 has 4 divisors (see below), whose sum is σ = 135357370444. Its totient is φ = 135353052000.

The previous prime is 135355211219. The next prime is 135355211237. The reversal of 135355211221 is 122112553531.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122112553531 = 191 ⋅639332741.

It can be written as a sum of positive squares in 2 ways, for example, as 4564488721 + 130790722500 = 67561^2 + 361650^2 .

It is a cyclic number.

It is not a de Polignac number, because 135355211221 - 2¹ = 135355211219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135355211281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 982680 + ... + 1111921.

It is an arithmetic number, because the mean of its divisors is an integer number (33839342611).

Almost surely, 2^135355211221 is an apocalyptic number.

It is an amenable number.

135355211221 is a deficient number, since it is larger than the sum of its proper divisors (2159223).

135355211221 is an equidigital number, since it uses as much as digits as its factorization.

135355211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2159222.

The product of its digits is 9000, while the sum is 31.

Adding to 135355211221 its reverse (122112553531), we get a palindrome (257467764752).

The spelling of 135355211221 in words is "one hundred thirty-five billion, three hundred fifty-five million, two hundred eleven thousand, two hundred twenty-one".