991998443 has 2 divisors, whose sum is σ = 991998444. Its totient is φ = 991998442.

The previous prime is 991998437. The next prime is 991998457. The reversal of 991998443 is 344899199.

It is a weak prime.

991998443 is a truncatable prime.

It is a cyclic number.

It is not a de Polignac number, because 991998443 - 2⁸ = 991998187 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991998473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495999221 + 495999222.

It is an arithmetic number, because the mean of its divisors is an integer number (495999222).

Almost surely, 2^991998443 is an apocalyptic number.

991998443 is a deficient number, since it is larger than the sum of its proper divisors (1).

991998443 is an equidigital number, since it uses as much as digits as its factorization.

991998443 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2519424, while the sum is 56.

The square root of 991998443 is about 31496.0067786378. The cubic root of 991998443 is about 997.3256686609.

The spelling of 991998443 in words is "nine hundred ninety-one million, nine hundred ninety-eight thousand, four hundred forty-three".