1020636521 has 2 divisors, whose sum is σ = 1020636522. Its totient is φ = 1020636520.

The previous prime is 1020636503. The next prime is 1020636541. The reversal of 1020636521 is 1256360201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 890425600 + 130210921 = 29840^2 + 11411^2 .

It is an emirp because it is prime and its reverse (1256360201) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1020636521 is a prime.

It is not a weakly prime, because it can be changed into another prime (1020636541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510318260 + 510318261.

It is an arithmetic number, because the mean of its divisors is an integer number (510318261).

Almost surely, 2^1020636521 is an apocalyptic number.

It is an amenable number.

1020636521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020636521 is an equidigital number, since it uses as much as digits as its factorization.

1020636521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 1020636521 is about 31947.4024139679. The cubic root of 1020636521 is about 1006.8320570301.

Adding to 1020636521 its reverse (1256360201), we get a palindrome (2276996722).

The spelling of 1020636521 in words is "one billion, twenty million, six hundred thirty-six thousand, five hundred twenty-one".