28820997 has 6 divisors (see below), whose sum is σ = 41630342. Its totient is φ = 19213992.

The previous prime is 28820993. The next prime is 28821049. The reversal of 28820997 is 79902882.

It can be written as a sum of positive squares in only one way, i.e., 19766916 + 9054081 = 4446^2 + 3009^2 .

It is not a de Polignac number, because 28820997 - 2² = 28820993 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 (28820993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1601158 + ... + 1601175.

Almost surely, 2^28820997 is an apocalyptic number.

It is an amenable number.

28820997 is a deficient number, since it is larger than the sum of its proper divisors (12809345).

28820997 is a wasteful number, since it uses less digits than its factorization.

28820997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3202339 (or 3202336 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 28820997 is about 5368.5190695386. The cubic root of 28820997 is about 306.5982465245.

The spelling of 28820997 in words is "twenty-eight million, eight hundred twenty thousand, nine hundred ninety-seven".