1998243969 has 4 divisors (see below), whose sum is σ = 2664325296. Its totient is φ = 1332162644.

The previous prime is 1998243959. The next prime is 1998243997. The reversal of 1998243969 is 9693428991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9693428991 = 3 ⋅3231142997.

It is a cyclic number.

It is not a de Polignac number, because 1998243969 - 2⁴ = 1998243953 is a prime.

It is a super-2 number, since 2×1998243969² = 7985957919289745922, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1998243959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 333040659 + ... + 333040664.

It is an arithmetic number, because the mean of its divisors is an integer number (666081324).

Almost surely, 2^1998243969 is an apocalyptic number.

It is an amenable number.

1998243969 is a deficient number, since it is larger than the sum of its proper divisors (666081327).

1998243969 is an equidigital number, since it uses as much as digits as its factorization.

1998243969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666081326.

The product of its digits is 7558272, while the sum is 60.

The square root of 1998243969 is about 44701.7222151451. The cubic root of 1998243969 is about 1259.5521985179.

The spelling of 1998243969 in words is "one billion, nine hundred ninety-eight million, two hundred forty-three thousand, nine hundred sixty-nine".