133751809 has 4 divisors (see below), whose sum is σ = 134311680. Its totient is φ = 133191940.

The previous prime is 133751797. The next prime is 133751861. The reversal of 133751809 is 908157331.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 908157331 = 1213 ⋅748687.

It is a cyclic number.

It is not a de Polignac number, because 133751809 - 2⁹ = 133751297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133757809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279577 + ... + 280054.

It is an arithmetic number, because the mean of its divisors is an integer number (33577920).

Almost surely, 2^133751809 is an apocalyptic number.

It is an amenable number.

133751809 is a deficient number, since it is larger than the sum of its proper divisors (559871).

133751809 is an equidigital number, since it uses as much as digits as its factorization.

133751809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559870.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 133751809 is about 11565.1117158461. Note that the first 3 decimals coincide. The cubic root of 133751809 is about 511.4068664965.

The spelling of 133751809 in words is "one hundred thirty-three million, seven hundred fifty-one thousand, eight hundred nine".