15910981 has 2 divisors, whose sum is σ = 15910982. Its totient is φ = 15910980.

The previous prime is 15910949. The next prime is 15910987. The reversal of 15910981 is 18901951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10458756 + 5452225 = 3234^2 + 2335^2 .

It is an emirp because it is prime and its reverse (18901951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15910981 - 2⁵ = 15910949 is a prime.

It is a super-2 number, since 2×15910981² = 506318632764722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15910987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7955490 + 7955491.

It is an arithmetic number, because the mean of its divisors is an integer number (7955491).

Almost surely, 2^15910981 is an apocalyptic number.

It is an amenable number.

15910981 is a deficient number, since it is larger than the sum of its proper divisors (1).

15910981 is an equidigital number, since it uses as much as digits as its factorization.

15910981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 34.

The square root of 15910981 is about 3988.8571044849. The cubic root of 15910981 is about 251.5160201487.

The spelling of 15910981 in words is "fifteen million, nine hundred ten thousand, nine hundred eighty-one".