135210991 has 4 divisors (see below), whose sum is σ = 135273672. Its totient is φ = 135148312.

The previous prime is 135210947. The next prime is 135211009. The reversal of 135210991 is 199012531.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 135210991 - 2⁷ = 135210863 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135210191) 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, 27985 + ... + 32458.

It is an arithmetic number, because the mean of its divisors is an integer number (33818418).

Almost surely, 2^135210991 is an apocalyptic number.

135210991 is a deficient number, since it is larger than the sum of its proper divisors (62681).

135210991 is an equidigital number, since it uses as much as digits as its factorization.

135210991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62680.

The product of its (nonzero) digits is 2430, while the sum is 31.

The square root of 135210991 is about 11628.0261007619. The cubic root of 135210991 is about 513.2598964024.

The spelling of 135210991 in words is "one hundred thirty-five million, two hundred ten thousand, nine hundred ninety-one".