998951561 has 2 divisors, whose sum is σ = 998951562. Its totient is φ = 998951560.

The previous prime is 998951557. The next prime is 998951587. The reversal of 998951561 is 165159899.

998951561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 932935936 + 66015625 = 30544^2 + 8125^2 .

It is a cyclic number.

It is not a de Polignac number, because 998951561 - 2² = 998951557 is a prime.

It is not a weakly prime, because it can be changed into another prime (998951521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499475780 + 499475781.

It is an arithmetic number, because the mean of its divisors is an integer number (499475781).

Almost surely, 2^998951561 is an apocalyptic number.

It is an amenable number.

998951561 is a deficient number, since it is larger than the sum of its proper divisors (1).

998951561 is an equidigital number, since it uses as much as digits as its factorization.

998951561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 874800, while the sum is 53.

The square root of 998951561 is about 31606.1949782001. The cubic root of 998951561 is about 999.6503981261.

The spelling of 998951561 in words is "nine hundred ninety-eight million, nine hundred fifty-one thousand, five hundred sixty-one".