16561913 has 2 divisors, whose sum is σ = 16561914. Its totient is φ = 16561912.

The previous prime is 16561889. The next prime is 16561969. The reversal of 16561913 is 31916561.

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., 12054784 + 4507129 = 3472^2 + 2123^2 .

It is a cyclic number.

It is not a de Polignac number, because 16561913 - 2¹² = 16557817 is a prime.

It is a super-3 number, since 3×16561913³ (a number of 23 digits) contains 333 as substring.

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 16561913.

It is not a weakly prime, because it can be changed into another prime (16561313) 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, 8280956 + 8280957.

It is an arithmetic number, because the mean of its divisors is an integer number (8280957).

Almost surely, 2^16561913 is an apocalyptic number.

It is an amenable number.

16561913 is a deficient number, since it is larger than the sum of its proper divisors (1).

16561913 is an equidigital number, since it uses as much as digits as its factorization.

16561913 is an odious number, because the sum of its binary digits is odd.

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

The square root of 16561913 is about 4069.6330301392. The cubic root of 16561913 is about 254.9001941852.

The spelling of 16561913 in words is "sixteen million, five hundred sixty-one thousand, nine hundred thirteen".