16565551 has 2 divisors, whose sum is σ = 16565552. Its totient is φ = 16565550.

The previous prime is 16565539. The next prime is 16565561. The reversal of 16565551 is 15556561.

It is a strong prime.

It is an emirp because it is prime and its reverse (15556561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16565551 - 2⁵ = 16565519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16565561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8282775 + 8282776.

It is an arithmetic number, because the mean of its divisors is an integer number (8282776).

Almost surely, 2^16565551 is an apocalyptic number.

16565551 is a deficient number, since it is larger than the sum of its proper divisors (1).

16565551 is an equidigital number, since it uses as much as digits as its factorization.

16565551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22500, while the sum is 34.

The square root of 16565551 is about 4070.0799746442. The cubic root of 16565551 is about 254.9188566633.

The spelling of 16565551 in words is "sixteen million, five hundred sixty-five thousand, five hundred fifty-one".