997989799 has 4 divisors (see below), whose sum is σ = 998178400. Its totient is φ = 997801200.

The previous prime is 997989793. The next prime is 997989821.

997989799 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 997989799 - 2⁹ = 997989287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997989793) 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 in 3 ways as a sum of consecutive naturals, for example, 86127 + ... + 97024.

It is an arithmetic number, because the mean of its divisors is an integer number (249544600).

Almost surely, 2^997989799 is an apocalyptic number.

997989799 is a deficient number, since it is larger than the sum of its proper divisors (188601).

997989799 is a wasteful number, since it uses less digits than its factorization.

997989799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188600.

The product of its digits is 208324872, while the sum is 76.

The square root of 997989799 is about 31590.9765439437. The cubic root of 997989799 is about 999.3294835081.

The spelling of 997989799 in words is "nine hundred ninety-seven million, nine hundred eighty-nine thousand, seven hundred ninety-nine".