135020021 has 2 divisors, whose sum is σ = 135020022. Its totient is φ = 135020020.

The previous prime is 135019999. The next prime is 135020047. The reversal of 135020021 is 120020531.

It is a happy number.

135020021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 86229796 + 48790225 = 9286^2 + 6985^2 .

It is a cyclic number.

It is not a de Polignac number, because 135020021 - 2¹⁸ = 134757877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 135019978 and 135020005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135020071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67510010 + 67510011.

It is an arithmetic number, because the mean of its divisors is an integer number (67510011).

Almost surely, 2^135020021 is an apocalyptic number.

It is an amenable number.

135020021 is a deficient number, since it is larger than the sum of its proper divisors (1).

135020021 is an equidigital number, since it uses as much as digits as its factorization.

135020021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 135020021 is about 11619.8115733432. The cubic root of 135020021 is about 513.0181423261.

Adding to 135020021 its reverse (120020531), we get a palindrome (255040552).

The spelling of 135020021 in words is "one hundred thirty-five million, twenty thousand, twenty-one".