1998224861 has 2 divisors, whose sum is σ = 1998224862. Its totient is φ = 1998224860.

The previous prime is 1998224821. The next prime is 1998224867. The reversal of 1998224861 is 1684228991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1489496836 + 508728025 = 38594^2 + 22555^2 .

It is an emirp because it is prime and its reverse (1684228991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1998224861 - 2¹⁴ = 1998208477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1998224867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999112430 + 999112431.

It is an arithmetic number, because the mean of its divisors is an integer number (999112431).

Almost surely, 2^1998224861 is an apocalyptic number.

It is an amenable number.

1998224861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998224861 is an equidigital number, since it uses as much as digits as its factorization.

1998224861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 497664, while the sum is 50.

The square root of 1998224861 is about 44701.5084868509. The cubic root of 1998224861 is about 1259.5481837261.

The spelling of 1998224861 in words is "one billion, nine hundred ninety-eight million, two hundred twenty-four thousand, eight hundred sixty-one".