133555813 has 4 divisors (see below), whose sum is σ = 136075788. Its totient is φ = 131035840.

The previous prime is 133555801. The next prime is 133555823. The reversal of 133555813 is 318555331.

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 52969284 + 80586529 = 7278^2 + 8977^2 .

It is a cyclic number.

It is not a de Polignac number, because 133555813 - 2²¹ = 131458661 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 (133555823) 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, 1259908 + ... + 1260013.

It is an arithmetic number, because the mean of its divisors is an integer number (34018947).

Almost surely, 2^133555813 is an apocalyptic number.

It is an amenable number.

133555813 is a deficient number, since it is larger than the sum of its proper divisors (2519975).

133555813 is an equidigital number, since it uses as much as digits as its factorization.

133555813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2519974.

The product of its digits is 27000, while the sum is 34.

The square root of 133555813 is about 11556.6350206278. The cubic root of 133555813 is about 511.1569441448.

The spelling of 133555813 in words is "one hundred thirty-three million, five hundred fifty-five thousand, eight hundred thirteen".