997728189 has 16 divisors (see below), whose sum is σ = 1343682432. Its totient is φ = 658477568.

The previous prime is 997728187. The next prime is 997728217. The reversal of 997728189 is 981827799.

It is a cyclic number.

It is not a de Polignac number, because 997728189 - 2¹ = 997728187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997728187) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 462337 + ... + 464489.

It is an arithmetic number, because the mean of its divisors is an integer number (83980152).

Almost surely, 2^997728189 is an apocalyptic number.

It is an amenable number.

997728189 is a deficient number, since it is larger than the sum of its proper divisors (345954243).

997728189 is a wasteful number, since it uses less digits than its factorization.

997728189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3636.

The product of its digits is 4572288, while the sum is 60.

The square root of 997728189 is about 31586.8356914712. The cubic root of 997728189 is about 999.2421554834.

The spelling of 997728189 in words is "nine hundred ninety-seven million, seven hundred twenty-eight thousand, one hundred eighty-nine".