135999731 has 4 divisors (see below), whose sum is σ = 155428272. Its totient is φ = 116571192.

The previous prime is 135999727. The next prime is 135999751. The reversal of 135999731 is 137999531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137999531 = 6619 ⋅20849.

It is a cyclic number.

It is not a de Polignac number, because 135999731 - 2² = 135999727 is a prime.

It is a super-2 number, since 2×135999731² = 36991853664144722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135999751) 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, 9714260 + ... + 9714273.

It is an arithmetic number, because the mean of its divisors is an integer number (38857068).

Almost surely, 2^135999731 is an apocalyptic number.

135999731 is a deficient number, since it is larger than the sum of its proper divisors (19428541).

135999731 is an equidigital number, since it uses as much as digits as its factorization.

135999731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19428540.

The product of its digits is 229635, while the sum is 47.

The square root of 135999731 is about 11661.8922564050. The cubic root of 135999731 is about 514.2559790752.

The spelling of 135999731 in words is "one hundred thirty-five million, nine hundred ninety-nine thousand, seven hundred thirty-one".