1202021561581 has 2 divisors, whose sum is σ = 1202021561582. Its totient is φ = 1202021561580.

The previous prime is 1202021561567. The next prime is 1202021561669. The reversal of 1202021561581 is 1851651202021.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1171895016681 + 30126544900 = 1082541^2 + 173570^2 .

It is a cyclic number.

It is not a de Polignac number, because 1202021561581 - 2¹⁷ = 1202021430509 is a prime.

It is a super-2 number, since 2×1202021561581² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1202021561981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 601010780790 + 601010780791.

It is an arithmetic number, because the mean of its divisors is an integer number (601010780791).

Almost surely, 2^{1202021561581} is an apocalyptic number.

It is an amenable number.

1202021561581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1202021561581 is an equidigital number, since it uses as much as digits as its factorization.

1202021561581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9600, while the sum is 34.

The spelling of 1202021561581 in words is "one trillion, two hundred two billion, twenty-one million, five hundred sixty-one thousand, five hundred eighty-one".