42020321521 has 2 divisors, whose sum is σ = 42020321522. Its totient is φ = 42020321520.

The previous prime is 42020321507. The next prime is 42020321537. The reversal of 42020321521 is 12512302024.

It is a happy number.

42020321521 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., 36038845921 + 5981475600 = 189839^2 + 77340^2 .

It is a cyclic number.

It is not a de Polignac number, because 42020321521 - 2⁹ = 42020321009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 42020321492 and 42020321501.

It is not a weakly prime, because it can be changed into another prime (42020321821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21010160760 + 21010160761.

It is an arithmetic number, because the mean of its divisors is an integer number (21010160761).

Almost surely, 2^42020321521 is an apocalyptic number.

It is an amenable number.

42020321521 is a deficient number, since it is larger than the sum of its proper divisors (1).

42020321521 is an equidigital number, since it uses as much as digits as its factorization.

42020321521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 42020321521 its reverse (12512302024), we get a palindrome (54532623545).

The spelling of 42020321521 in words is "forty-two billion, twenty million, three hundred twenty-one thousand, five hundred twenty-one".