16319561 has 2 divisors, whose sum is σ = 16319562. Its totient is φ = 16319560.

The previous prime is 16319557. The next prime is 16319579. The reversal of 16319561 is 16591361.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15405625 + 913936 = 3925^2 + 956^2 .

It is a cyclic number.

It is not a de Polignac number, because 16319561 - 2² = 16319557 is a prime.

It is not a weakly prime, because it can be changed into another prime (16319521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8159780 + 8159781.

It is an arithmetic number, because the mean of its divisors is an integer number (8159781).

Almost surely, 2^16319561 is an apocalyptic number.

It is an amenable number.

16319561 is a deficient number, since it is larger than the sum of its proper divisors (1).

16319561 is an equidigital number, since it uses as much as digits as its factorization.

16319561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4860, while the sum is 32.

The square root of 16319561 is about 4039.7476406330. The cubic root of 16319561 is about 253.6507538143.

The spelling of 16319561 in words is "sixteen million, three hundred nineteen thousand, five hundred sixty-one".