28787897 has 4 divisors (see below), whose sum is σ = 28822500. Its totient is φ = 28753296.

The previous prime is 28787893. The next prime is 28787903. The reversal of 28787897 is 79878782.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13957696 + 14830201 = 3736^2 + 3851^2 .

It is a cyclic number.

It is not a de Polignac number, because 28787897 - 2² = 28787893 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28787893) 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, 16022 + ... + 17727.

It is an arithmetic number, because the mean of its divisors is an integer number (7205625).

Almost surely, 2^28787897 is an apocalyptic number.

It is an amenable number.

28787897 is a deficient number, since it is larger than the sum of its proper divisors (34603).

28787897 is an equidigital number, since it uses as much as digits as its factorization.

28787897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34602.

The product of its digits is 3161088, while the sum is 56.

The square root of 28787897 is about 5365.4353970577. The cubic root of 28787897 is about 306.4808287789.

The spelling of 28787897 in words is "twenty-eight million, seven hundred eighty-seven thousand, eight hundred ninety-seven".