135551971 has 4 divisors (see below), whose sum is σ = 136949512. Its totient is φ = 134154432.

The previous prime is 135551963. The next prime is 135551981. The reversal of 135551971 is 179155531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 179155531 = 193 ⋅928267.

It is a cyclic number.

It is not a de Polignac number, because 135551971 - 2³ = 135551963 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 135551971.

It is not an unprimeable number, because it can be changed into a prime (135551981) 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, 698625 + ... + 698818.

It is an arithmetic number, because the mean of its divisors is an integer number (34237378).

Almost surely, 2^135551971 is an apocalyptic number.

135551971 is a deficient number, since it is larger than the sum of its proper divisors (1397541).

135551971 is an equidigital number, since it uses as much as digits as its factorization.

135551971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1397540.

The product of its digits is 23625, while the sum is 37.

The square root of 135551971 is about 11642.6788584071. The cubic root of 135551971 is about 513.6909867234.

The spelling of 135551971 in words is "one hundred thirty-five million, five hundred fifty-one thousand, nine hundred seventy-one".