989959561 has 2 divisors, whose sum is σ = 989959562. Its totient is φ = 989959560.

The previous prime is 989959511. The next prime is 989959577. The reversal of 989959561 is 165959989.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 988473600 + 1485961 = 31440^2 + 1219^2 .

It is a cyclic number.

It is not a de Polignac number, because 989959561 - 2⁷ = 989959433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 989959561.

It is not a weakly prime, because it can be changed into another prime (989959511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494979780 + 494979781.

It is an arithmetic number, because the mean of its divisors is an integer number (494979781).

Almost surely, 2^989959561 is an apocalyptic number.

It is an amenable number.

989959561 is a deficient number, since it is larger than the sum of its proper divisors (1).

989959561 is an equidigital number, since it uses as much as digits as its factorization.

989959561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7873200, while the sum is 61.

The square root of 989959561 is about 31463.6228206480. The cubic root of 989959561 is about 996.6419229411.

The spelling of 989959561 in words is "nine hundred eighty-nine million, nine hundred fifty-nine thousand, five hundred sixty-one".