15565656551 has 2 divisors, whose sum is σ = 15565656552. Its totient is φ = 15565656550.

The previous prime is 15565656541. The next prime is 15565656553.

15565656551 is nontrivially palindromic in base 10.

It is a strong prime.

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 15565656551 - 2⁶ = 15565656487 is a prime.

Together with 15565656553, it forms a pair of twin primes.

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 15565656551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15565656553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7782828275 + 7782828276.

It is an arithmetic number, because the mean of its divisors is an integer number (7782828276).

Almost surely, 2^15565656551 is an apocalyptic number.

15565656551 is a deficient number, since it is larger than the sum of its proper divisors (1).

15565656551 is an equidigital number, since it uses as much as digits as its factorization.

15565656551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3375000, while the sum is 50.

The spelling of 15565656551 in words is "fifteen billion, five hundred sixty-five million, six hundred fifty-six thousand, five hundred fifty-one".