997813989 has 12 divisors (see below), whose sum is σ = 1442069772. Its totient is φ = 664848000.

The previous prime is 997813979. The next prime is 997814009. The reversal of 997813989 is 989318799.

It can be written as a sum of positive squares in 2 ways, for example, as 40220964 + 957593025 = 6342^2 + 30945^2 .

It is not a de Polignac number, because 997813989 - 2¹⁹ = 997289701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997813919) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12052 + ... + 46269.

It is an arithmetic number, because the mean of its divisors is an integer number (120172481).

Almost surely, 2^997813989 is an apocalyptic number.

It is an amenable number.

997813989 is a deficient number, since it is larger than the sum of its proper divisors (444255783).

997813989 is a wasteful number, since it uses less digits than its factorization.

997813989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60228 (or 60225 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 63.

The square root of 997813989 is about 31588.1938230093. The cubic root of 997813989 is about 999.2707980604.

The spelling of 997813989 in words is "nine hundred ninety-seven million, eight hundred thirteen thousand, nine hundred eighty-nine".