28204997 has 4 divisors (see below), whose sum is σ = 28667436. Its totient is φ = 27742560.

The previous prime is 28204993. The next prime is 28204999. The reversal of 28204997 is 79940282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79940282 = 2 ⋅39970141.

It can be written as a sum of positive squares in 2 ways, for example, as 9247681 + 18957316 = 3041^2 + 4354^2 .

It is a cyclic number.

It is not a de Polignac number, because 28204997 - 2² = 28204993 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 (28204991) 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, 231128 + ... + 231249.

It is an arithmetic number, because the mean of its divisors is an integer number (7166859).

Almost surely, 2^28204997 is an apocalyptic number.

It is an amenable number.

28204997 is a deficient number, since it is larger than the sum of its proper divisors (462439).

28204997 is an equidigital number, since it uses as much as digits as its factorization.

28204997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462438.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 28204997 is about 5310.8376928692. The cubic root of 28204997 is about 304.3981574551.

The spelling of 28204997 in words is "twenty-eight million, two hundred four thousand, nine hundred ninety-seven".