135820909 has 4 divisors (see below), whose sum is σ = 155223904. Its totient is φ = 116417916.

The previous prime is 135820907. The next prime is 135820913. The reversal of 135820909 is 909028531.

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: 909028531 = 31 ⋅29323501.

It is a cyclic number.

It is not a de Polignac number, because 135820909 - 2¹ = 135820907 is a prime.

It is a super-3 number, since 3×135820909³ (a number of 25 digits) contains 333 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 (135820901) 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, 9701487 + ... + 9701500.

It is an arithmetic number, because the mean of its divisors is an integer number (38805976).

Almost surely, 2^135820909 is an apocalyptic number.

It is an amenable number.

135820909 is a deficient number, since it is larger than the sum of its proper divisors (19402995).

135820909 is an equidigital number, since it uses as much as digits as its factorization.

135820909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19402994.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 135820909 is about 11654.2227969093. Note that the first 3 decimals coincide. The cubic root of 135820909 is about 514.0304869198.

The spelling of 135820909 in words is "one hundred thirty-five million, eight hundred twenty thousand, nine hundred nine".