135318221356721 has 16 divisors (see below), whose sum is σ = 146258304401664. Its totient is φ = 124454493805824.

The previous prime is 135318221356663. The next prime is 135318221356751. The reversal of 135318221356721 is 127653122813531.

It is a de Polignac number, because none of the positive numbers 2^k-135318221356721 is a prime.

It is a super-2 number, since 2×135318221356721² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 135318221356721.

It is not an unprimeable number, because it can be changed into a prime (135318221356751) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3916841 + ... + 16910886.

It is an arithmetic number, because the mean of its divisors is an integer number (9141144025104).

Almost surely, 2^{135318221356721} is an apocalyptic number.

It is an amenable number.

135318221356721 is a deficient number, since it is larger than the sum of its proper divisors (10940083044943).

135318221356721 is a wasteful number, since it uses less digits than its factorization.

135318221356721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20829560.

The product of its digits is 1814400, while the sum is 50.

The spelling of 135318221356721 in words is "one hundred thirty-five trillion, three hundred eighteen billion, two hundred twenty-one million, three hundred fifty-six thousand, seven hundred twenty-one".