136721311 has 4 divisors (see below), whose sum is σ = 136754800. Its totient is φ = 136687824.

The previous prime is 136721309. The next prime is 136721317. The reversal of 136721311 is 113127631.

136721311 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 113127631 = 277 ⋅408403.

It is a cyclic number.

It is not a de Polignac number, because 136721311 - 2¹ = 136721309 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 (136721317) 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, 9606 + ... + 19123.

It is an arithmetic number, because the mean of its divisors is an integer number (34188700).

Almost surely, 2^136721311 is an apocalyptic number.

136721311 is a deficient number, since it is larger than the sum of its proper divisors (33489).

136721311 is an equidigital number, since it uses as much as digits as its factorization.

136721311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33488.

The product of its digits is 756, while the sum is 25.

The square root of 136721311 is about 11692.7888461222. The cubic root of 136721311 is about 515.1638790995.

Adding to 136721311 its reverse (113127631), we get a palindrome (249848942).

The spelling of 136721311 in words is "one hundred thirty-six million, seven hundred twenty-one thousand, three hundred eleven".