135899781 has 4 divisors (see below), whose sum is σ = 181199712. Its totient is φ = 90599852.

The previous prime is 135899773. The next prime is 135899807. The reversal of 135899781 is 187998531.

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.

It is a cyclic number.

It is not a de Polignac number, because 135899781 - 2³ = 135899773 is a prime.

It is a super-2 number, since 2×135899781² = 36937500951695922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (135899711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22649961 + ... + 22649966.

It is an arithmetic number, because the mean of its divisors is an integer number (45299928).

Almost surely, 2^135899781 is an apocalyptic number.

It is an amenable number.

135899781 is a deficient number, since it is larger than the sum of its proper divisors (45299931).

135899781 is an equidigital number, since it uses as much as digits as its factorization.

135899781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45299930.

The product of its digits is 544320, while the sum is 51.

The square root of 135899781 is about 11657.6061436300. The cubic root of 135899781 is about 514.1299678407.

The spelling of 135899781 in words is "one hundred thirty-five million, eight hundred ninety-nine thousand, seven hundred eighty-one".