15305981 has 2 divisors, whose sum is σ = 15305982. Its totient is φ = 15305980.

The previous prime is 15305977. The next prime is 15305987. The reversal of 15305981 is 18950351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12313081 + 2992900 = 3509^2 + 1730^2 .

It is a cyclic number.

It is not a de Polignac number, because 15305981 - 2² = 15305977 is a prime.

It is a super-2 number, since 2×15305981² = 468546108744722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15305987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7652990 + 7652991.

It is an arithmetic number, because the mean of its divisors is an integer number (7652991).

Almost surely, 2^15305981 is an apocalyptic number.

It is an amenable number.

15305981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15305981 is an equidigital number, since it uses as much as digits as its factorization.

15305981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 32.

The square root of 15305981 is about 3912.2859046854. The cubic root of 15305981 is about 248.2868526533.

The spelling of 15305981 in words is "fifteen million, three hundred five thousand, nine hundred eighty-one".