135984721 has 4 divisors (see below), whose sum is σ = 136011700. Its totient is φ = 135957744.

The previous prime is 135984713. The next prime is 135984727. The reversal of 135984721 is 127489531.

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 97792321 + 38192400 = 9889^2 + 6180^2 .

It is a cyclic number.

It is not a de Polignac number, because 135984721 - 2³ = 135984713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135984727) 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, 3426 + ... + 16843.

It is an arithmetic number, because the mean of its divisors is an integer number (34002925).

Almost surely, 2^135984721 is an apocalyptic number.

It is an amenable number.

135984721 is a deficient number, since it is larger than the sum of its proper divisors (26979).

135984721 is an equidigital number, since it uses as much as digits as its factorization.

135984721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26978.

The product of its digits is 60480, while the sum is 40.

The square root of 135984721 is about 11661.2486895701. The cubic root of 135984721 is about 514.2370592676.

The spelling of 135984721 in words is "one hundred thirty-five million, nine hundred eighty-four thousand, seven hundred twenty-one".