28197649 has 4 divisors (see below), whose sum is σ = 28260900. Its totient is φ = 28134400.

The previous prime is 28197647. The next prime is 28197731. The reversal of 28197649 is 94679182.

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 8661249 + 19536400 = 2943^2 + 4420^2 .

It is a cyclic number.

It is not a de Polignac number, because 28197649 - 2¹ = 28197647 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28197599 and 28197608.

It is not an unprimeable number, because it can be changed into a prime (28197641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30952 + ... + 31849.

It is an arithmetic number, because the mean of its divisors is an integer number (7065225).

Almost surely, 2^28197649 is an apocalyptic number.

It is an amenable number.

28197649 is a deficient number, since it is larger than the sum of its proper divisors (63251).

28197649 is an equidigital number, since it uses as much as digits as its factorization.

28197649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63250.

The product of its digits is 217728, while the sum is 46.

The square root of 28197649 is about 5310.1458548707. The cubic root of 28197649 is about 304.3717211002.

The spelling of 28197649 in words is "twenty-eight million, one hundred ninety-seven thousand, six hundred forty-nine".