136521066221 has 4 divisors (see below), whose sum is σ = 137517570492. Its totient is φ = 135524561952.

The previous prime is 136521066211. The next prime is 136521066247. The reversal of 136521066221 is 122660125631.

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 100735777321 + 35785288900 = 317389^2 + 189170^2 .

It is a cyclic number.

It is not a de Polignac number, because 136521066221 - 2²² = 136516871917 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 (136521066211) 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, 498251930 + ... + 498252203.

It is an arithmetic number, because the mean of its divisors is an integer number (34379392623).

Almost surely, 2^136521066221 is an apocalyptic number.

It is an amenable number.

136521066221 is a deficient number, since it is larger than the sum of its proper divisors (996504271).

136521066221 is an equidigital number, since it uses as much as digits as its factorization.

136521066221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 996504270.

The product of its (nonzero) digits is 25920, while the sum is 35.

The spelling of 136521066221 in words is "one hundred thirty-six billion, five hundred twenty-one million, sixty-six thousand, two hundred twenty-one".