28788997 has 4 divisors (see below), whose sum is σ = 29567116. Its totient is φ = 28010880.

The previous prime is 28788983. The next prime is 28789001. The reversal of 28788997 is 79988782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79988782 = 2 ⋅39994391.

It can be written as a sum of positive squares in 2 ways, for example, as 20802721 + 7986276 = 4561^2 + 2826^2 .

It is a cyclic number.

It is not a de Polignac number, because 28788997 - 2⁷ = 28788869 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 (28782997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 389004 + ... + 389077.

It is an arithmetic number, because the mean of its divisors is an integer number (7391779).

Almost surely, 2^28788997 is an apocalyptic number.

It is an amenable number.

28788997 is a deficient number, since it is larger than the sum of its proper divisors (778119).

28788997 is an equidigital number, since it uses as much as digits as its factorization.

28788997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778118.

The product of its digits is 4064256, while the sum is 58.

The square root of 28788997 is about 5365.5379040689. The cubic root of 28788997 is about 306.4847323246.

The spelling of 28788997 in words is "twenty-eight million, seven hundred eighty-eight thousand, nine hundred ninety-seven".