16699561 has 2 divisors, whose sum is σ = 16699562. Its totient is φ = 16699560.

The previous prime is 16699531. The next prime is 16699567. The reversal of 16699561 is 16599661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12033961 + 4665600 = 3469^2 + 2160^2 .

It is a cyclic number.

It is not a de Polignac number, because 16699561 - 2⁷ = 16699433 is a prime.

It is not a weakly prime, because it can be changed into another prime (16699567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8349780 + 8349781.

It is an arithmetic number, because the mean of its divisors is an integer number (8349781).

Almost surely, 2^16699561 is an apocalyptic number.

It is an amenable number.

16699561 is a deficient number, since it is larger than the sum of its proper divisors (1).

16699561 is an equidigital number, since it uses as much as digits as its factorization.

16699561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 43.

The square root of 16699561 is about 4086.5096353734. The cubic root of 16699561 is about 255.6044152816.

The spelling of 16699561 in words is "sixteen million, six hundred ninety-nine thousand, five hundred sixty-one".