1015556561 has 2 divisors, whose sum is σ = 1015556562. Its totient is φ = 1015556560.

The previous prime is 1015556533. The next prime is 1015556567. The reversal of 1015556561 is 1656555101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 794112400 + 221444161 = 28180^2 + 14881^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1015556561 is a prime.

It is not a weakly prime, because it can be changed into another prime (1015556567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 507778280 + 507778281.

It is an arithmetic number, because the mean of its divisors is an integer number (507778281).

Almost surely, 2^1015556561 is an apocalyptic number.

It is an amenable number.

1015556561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1015556561 is an equidigital number, since it uses as much as digits as its factorization.

1015556561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22500, while the sum is 35.

The square root of 1015556561 is about 31867.7981824914. The cubic root of 1015556561 is about 1005.1588607237.

The spelling of 1015556561 in words is "one billion, fifteen million, five hundred fifty-six thousand, five hundred sixty-one".