981681109 has 2 divisors, whose sum is σ = 981681110. Its totient is φ = 981681108.

The previous prime is 981681091. The next prime is 981681121. The reversal of 981681109 is 901186189.

It is a happy number.

981681109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with previous prime (981681091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 812421009 + 169260100 = 28503^2 + 13010^2 .

It is a cyclic number.

It is not a de Polignac number, because 981681109 - 2¹⁵ = 981648341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (981681149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490840554 + 490840555.

It is an arithmetic number, because the mean of its divisors is an integer number (490840555).

Almost surely, 2^981681109 is an apocalyptic number.

It is an amenable number.

981681109 is a deficient number, since it is larger than the sum of its proper divisors (1).

981681109 is an equidigital number, since it uses as much as digits as its factorization.

981681109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 43.

The square root of 981681109 is about 31331.7907084801. The cubic root of 981681109 is about 993.8560319650.

The spelling of 981681109 in words is "nine hundred eighty-one million, six hundred eighty-one thousand, one hundred nine".