1660015561 has 2 divisors, whose sum is σ = 1660015562. Its totient is φ = 1660015560.

The previous prime is 1660015543. The next prime is 1660015573. The reversal of 1660015561 is 1655100661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1649903161 + 10112400 = 40619^2 + 3180^2 .

It is a cyclic number.

It is not a de Polignac number, because 1660015561 - 2⁵ = 1660015529 is a prime.

It is not a weakly prime, because it can be changed into another prime (1660015531) 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, 830007780 + 830007781.

It is an arithmetic number, because the mean of its divisors is an integer number (830007781).

Almost surely, 2^1660015561 is an apocalyptic number.

It is an amenable number.

1660015561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1660015561 is an equidigital number, since it uses as much as digits as its factorization.

1660015561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 1660015561 is about 40743.2885393411. The cubic root of 1660015561 is about 1184.0518473252.

The spelling of 1660015561 in words is "one billion, six hundred sixty million, fifteen thousand, five hundred sixty-one".