15943561 has 2 divisors, whose sum is σ = 15943562. Its totient is φ = 15943560.

The previous prime is 15943523. The next prime is 15943573. The reversal of 15943561 is 16534951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14107536 + 1836025 = 3756^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 15943561 - 2⁹ = 15943049 is a prime.

It is not a weakly prime, because it can be changed into another prime (15943661) 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, 7971780 + 7971781.

It is an arithmetic number, because the mean of its divisors is an integer number (7971781).

Almost surely, 2^15943561 is an apocalyptic number.

It is an amenable number.

15943561 is a deficient number, since it is larger than the sum of its proper divisors (1).

15943561 is an equidigital number, since it uses as much as digits as its factorization.

15943561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 34.

The square root of 15943561 is about 3992.9388925953. The cubic root of 15943561 is about 251.6875747338.

The spelling of 15943561 in words is "fifteen million, nine hundred forty-three thousand, five hundred sixty-one".