999898981 has 2 divisors, whose sum is σ = 999898982. Its totient is φ = 999898980.

The previous prime is 999898969. The next prime is 999899003. The reversal of 999898981 is 189898999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 972504225 + 27394756 = 31185^2 + 5234^2 .

It is a cyclic number.

It is not a de Polignac number, because 999898981 - 2¹⁵ = 999866213 is a prime.

It is a super-2 number, since 2×999898981² = 1999595944409676722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 999898981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999898951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499949490 + 499949491.

It is an arithmetic number, because the mean of its divisors is an integer number (499949491).

Almost surely, 2^999898981 is an apocalyptic number.

It is an amenable number.

999898981 is a deficient number, since it is larger than the sum of its proper divisors (1).

999898981 is an equidigital number, since it uses as much as digits as its factorization.

999898981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30233088, while the sum is 70.

The square root of 999898981 is about 31621.1793107088. The cubic root of 999898981 is about 999.9663258661.

The spelling of 999898981 in words is "nine hundred ninety-nine million, eight hundred ninety-eight thousand, nine hundred eighty-one".