133136821 has 4 divisors (see below), whose sum is σ = 133906572. Its totient is φ = 132367072.

The previous prime is 133136807. The next prime is 133136827. The reversal of 133136821 is 128631331.

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 102212100 + 30924721 = 10110^2 + 5561^2 .

It is a cyclic number.

It is not a de Polignac number, because 133136821 - 2⁹ = 133136309 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 133136821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133136827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 384616 + ... + 384961.

It is an arithmetic number, because the mean of its divisors is an integer number (33476643).

Almost surely, 2^133136821 is an apocalyptic number.

It is an amenable number.

133136821 is a deficient number, since it is larger than the sum of its proper divisors (769751).

133136821 is an equidigital number, since it uses as much as digits as its factorization.

133136821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769750.

The product of its digits is 2592, while the sum is 28.

The square root of 133136821 is about 11538.4930125212. The cubic root of 133136821 is about 510.6218494343.

The spelling of 133136821 in words is "one hundred thirty-three million, one hundred thirty-six thousand, eight hundred twenty-one".