135125021 has 2 divisors, whose sum is σ = 135125022. Its totient is φ = 135125020.

The previous prime is 135124973. The next prime is 135125041. The reversal of 135125021 is 120521531.

It is a happy number.

It is an a-pointer prime, because the next prime (135125041) can be obtained adding 135125021 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83083225 + 52041796 = 9115^2 + 7214^2 .

It is a cyclic number.

It is not a de Polignac number, because 135125021 - 2¹⁰ = 135123997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 135124984 and 135125002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135125041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67562510 + 67562511.

It is an arithmetic number, because the mean of its divisors is an integer number (67562511).

Almost surely, 2^135125021 is an apocalyptic number.

It is an amenable number.

135125021 is a deficient number, since it is larger than the sum of its proper divisors (1).

135125021 is an equidigital number, since it uses as much as digits as its factorization.

135125021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 135125021 is about 11624.3288408407. The cubic root of 135125021 is about 513.1510928499.

Adding to 135125021 its reverse (120521531), we get a palindrome (255646552).

The spelling of 135125021 in words is "one hundred thirty-five million, one hundred twenty-five thousand, twenty-one".