15909843661 has 2 divisors, whose sum is σ = 15909843662. Its totient is φ = 15909843660.

The previous prime is 15909843641. The next prime is 15909843727. The reversal of 15909843661 is 16634890951.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14597230761 + 1312612900 = 120819^2 + 36230^2 .

It is a cyclic number.

It is not a de Polignac number, because 15909843661 - 2²¹ = 15907746509 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15909843599 and 15909843608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15909843641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7954921830 + 7954921831.

It is an arithmetic number, because the mean of its divisors is an integer number (7954921831).

Almost surely, 2^15909843661 is an apocalyptic number.

It is an amenable number.

15909843661 is a deficient number, since it is larger than the sum of its proper divisors (1).

15909843661 is an equidigital number, since it uses as much as digits as its factorization.

15909843661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The spelling of 15909843661 in words is "fifteen billion, nine hundred nine million, eight hundred forty-three thousand, six hundred sixty-one".