1020605561 has 2 divisors, whose sum is σ = 1020605562. Its totient is φ = 1020605560.

The previous prime is 1020605543. The next prime is 1020605563. The reversal of 1020605561 is 1655060201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1007681536 + 12924025 = 31744^2 + 3595^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020605561 - 2¹⁴ = 1020589177 is a prime.

It is a super-2 number, since 2×1020605561² = 2083271422288249442, which contains 22 as substring.

Together with 1020605563, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1020605561.

It is not a weakly prime, because it can be changed into another prime (1020605563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510302780 + 510302781.

It is an arithmetic number, because the mean of its divisors is an integer number (510302781).

Almost surely, 2^1020605561 is an apocalyptic number.

It is an amenable number.

1020605561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020605561 is an equidigital number, since it uses as much as digits as its factorization.

1020605561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 1020605561 is about 31946.9178638566. The cubic root of 1020605561 is about 1006.8218765087.

Adding to 1020605561 its reverse (1655060201), we get a palindrome (2675665762).

The spelling of 1020605561 in words is "one billion, twenty million, six hundred five thousand, five hundred sixty-one".