15981344549 has 2 divisors, whose sum is σ = 15981344550. Its totient is φ = 15981344548.

The previous prime is 15981344441. The next prime is 15981344629. The reversal of 15981344549 is 94544318951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11049793924 + 4931550625 = 105118^2 + 70225^2 .

It is a cyclic number.

It is not a de Polignac number, because 15981344549 - 2⁸ = 15981344293 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 15981344549.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15981344749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7990672274 + 7990672275.

It is an arithmetic number, because the mean of its divisors is an integer number (7990672275).

Almost surely, 2^15981344549 is an apocalyptic number.

It is an amenable number.

15981344549 is a deficient number, since it is larger than the sum of its proper divisors (1).

15981344549 is an equidigital number, since it uses as much as digits as its factorization.

15981344549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3110400, while the sum is 53.

The spelling of 15981344549 in words is "fifteen billion, nine hundred eighty-one million, three hundred forty-four thousand, five hundred forty-nine".