15661648109 has 2 divisors, whose sum is σ = 15661648110. Its totient is φ = 15661648108.

The previous prime is 15661648087. The next prime is 15661648133. The reversal of 15661648109 is 90184616651.

15661648109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13297549225 + 2364098884 = 115315^2 + 48622^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15661648109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15661644109) 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, 7830824054 + 7830824055.

It is an arithmetic number, because the mean of its divisors is an integer number (7830824055).

Almost surely, 2^15661648109 is an apocalyptic number.

It is an amenable number.

15661648109 is a deficient number, since it is larger than the sum of its proper divisors (1).

15661648109 is an equidigital number, since it uses as much as digits as its factorization.

15661648109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 47.

The spelling of 15661648109 in words is "fifteen billion, six hundred sixty-one million, six hundred forty-eight thousand, one hundred nine".