1208521021 has 2 divisors, whose sum is σ = 1208521022. Its totient is φ = 1208521020.

The previous prime is 1208521001. The next prime is 1208521037. The reversal of 1208521021 is 1201258021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1075118521 + 133402500 = 32789^2 + 11550^2 .

It is a cyclic number.

It is not a de Polignac number, because 1208521021 - 2²⁵ = 1174966589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1208520983 and 1208521001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1208521001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 604260510 + 604260511.

It is an arithmetic number, because the mean of its divisors is an integer number (604260511).

Almost surely, 2^1208521021 is an apocalyptic number.

It is an amenable number.

1208521021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1208521021 is an equidigital number, since it uses as much as digits as its factorization.

1208521021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 1208521021 is about 34763.7889333139. The cubic root of 1208521021 is about 1065.1678990582.

Adding to 1208521021 its reverse (1201258021), we get a palindrome (2409779042).

The spelling of 1208521021 in words is "one billion, two hundred eight million, five hundred twenty-one thousand, twenty-one".