136821 has 8 divisors (see below), whose sum is σ = 185760. Its totient is φ = 89552.

The previous prime is 136813. The next prime is 136841. The reversal of 136821 is 128631.

136821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 136821 - 2³ = 136813 is a prime.

It is a Curzon number.

136821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (136811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 210 + ... + 563.

It is an arithmetic number, because the mean of its divisors is an integer number (23220).

2¹³⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

136821 is a deficient number, since it is larger than the sum of its proper divisors (48939).

136821 is an equidigital number, since it uses as much as digits as its factorization.

136821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 835.

The product of its digits is 288, while the sum is 21.

The square root of 136821 is about 369.8932278374. The cubic root of 136821 is about 51.5289057573.

The spelling of 136821 in words is "one hundred thirty-six thousand, eight hundred twenty-one".