136821311 has 4 divisors (see below), whose sum is σ = 149259624. Its totient is φ = 124383000.

The previous prime is 136821283. The next prime is 136821323. The reversal of 136821311 is 113128631.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-136821311 is a prime.

It is a super-2 number, since 2×136821311² = 37440142287517442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136821341) 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, 6219140 + ... + 6219161.

It is an arithmetic number, because the mean of its divisors is an integer number (37314906).

Almost surely, 2^136821311 is an apocalyptic number.

136821311 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

136821311 is a deficient number, since it is larger than the sum of its proper divisors (12438313).

136821311 is a wasteful number, since it uses less digits than its factorization.

136821311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12438312.

The product of its digits is 864, while the sum is 26.

The square root of 136821311 is about 11697.0642043207. The cubic root of 136821311 is about 515.2894479975.

Adding to 136821311 its reverse (113128631), we get a palindrome (249949942).

The spelling of 136821311 in words is "one hundred thirty-six million, eight hundred twenty-one thousand, three hundred eleven".