978145981 has 2 divisors, whose sum is σ = 978145982. Its totient is φ = 978145980.

The previous prime is 978145969. The next prime is 978145991. The reversal of 978145981 is 189541879.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 950488900 + 27657081 = 30830^2 + 5259^2 .

It is an emirp because it is prime and its reverse (189541879) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-978145981 is a prime.

It is a super-3 number, since 3×978145981³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (978145991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 489072990 + 489072991.

It is an arithmetic number, because the mean of its divisors is an integer number (489072991).

Almost surely, 2^978145981 is an apocalyptic number.

It is an amenable number.

978145981 is a deficient number, since it is larger than the sum of its proper divisors (1).

978145981 is an equidigital number, since it uses as much as digits as its factorization.

978145981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 52.

The square root of 978145981 is about 31275.3254339583. The cubic root of 978145981 is about 992.6616067131.

The spelling of 978145981 in words is "nine hundred seventy-eight million, one hundred forty-five thousand, nine hundred eighty-one".