28440649 has 2 divisors, whose sum is σ = 28440650. Its totient is φ = 28440648.

The previous prime is 28440647. The next prime is 28440661. The reversal of 28440649 is 94604482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21902400 + 6538249 = 4680^2 + 2557^2 .

It is a cyclic number.

It is not a de Polignac number, because 28440649 - 2¹ = 28440647 is a prime.

Together with 28440647, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (28440641) 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 as a sum of consecutive naturals, namely, 14220324 + 14220325.

It is an arithmetic number, because the mean of its divisors is an integer number (14220325).

Almost surely, 2^28440649 is an apocalyptic number.

It is an amenable number.

28440649 is a deficient number, since it is larger than the sum of its proper divisors (1).

28440649 is an equidigital number, since it uses as much as digits as its factorization.

28440649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55296, while the sum is 37.

The square root of 28440649 is about 5332.9774985462. The cubic root of 28440649 is about 305.2435535583.

The spelling of 28440649 in words is "twenty-eight million, four hundred forty thousand, six hundred forty-nine".