135444351221521 has 4 divisors (see below), whose sum is σ = 135933319998772. Its totient is φ = 134955382444272.

The previous prime is 135444351221423. The next prime is 135444351221603. The reversal of 135444351221521 is 125122153444531.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15015346001296 + 120429005220225 = 3874964^2 + 10974015^2 .

It is a cyclic number.

It is not a de Polignac number, because 135444351221521 - 2⁹ = 135444351221009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135444351221321) 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, 244484388210 + ... + 244484388763.

It is an arithmetic number, because the mean of its divisors is an integer number (33983329999693).

Almost surely, 2^{135444351221521} is an apocalyptic number.

It is an amenable number.

135444351221521 is a deficient number, since it is larger than the sum of its proper divisors (488968777251).

135444351221521 is an equidigital number, since it uses as much as digits as its factorization.

135444351221521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488968777250.

The product of its digits is 576000, while the sum is 43.

The spelling of 135444351221521 in words is "one hundred thirty-five trillion, four hundred forty-four billion, three hundred fifty-one million, two hundred twenty-one thousand, five hundred twenty-one".