135146021 has 2 divisors, whose sum is σ = 135146022. Its totient is φ = 135146020.

The previous prime is 135145987. The next prime is 135146023. The reversal of 135146021 is 120641531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122965921 + 12180100 = 11089^2 + 3490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135146021 is a prime.

Together with 135146023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135146023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67573010 + 67573011.

It is an arithmetic number, because the mean of its divisors is an integer number (67573011).

Almost surely, 2^135146021 is an apocalyptic number.

It is an amenable number.

135146021 is a deficient number, since it is larger than the sum of its proper divisors (1).

135146021 is an equidigital number, since it uses as much as digits as its factorization.

135146021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 135146021 is about 11625.2320837048. The cubic root of 135146021 is about 513.1776746891.

Adding to 135146021 its reverse (120641531), we get a palindrome (255787552).

The spelling of 135146021 in words is "one hundred thirty-five million, one hundred forty-six thousand, twenty-one".