28778713 has 4 divisors (see below), whose sum is σ = 28789668. Its totient is φ = 28767760.

The previous prime is 28778693. The next prime is 28778719. The reversal of 28778713 is 31787782.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 11539609 + 17239104 = 3397^2 + 4152^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28778713 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28778713.

It is not an unprimeable number, because it can be changed into a prime (28778719) 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 in 3 ways as a sum of consecutive naturals, for example, 1083 + ... + 7663.

It is an arithmetic number, because the mean of its divisors is an integer number (7197417).

Almost surely, 2^28778713 is an apocalyptic number.

It is an amenable number.

28778713 is a deficient number, since it is larger than the sum of its proper divisors (10955).

28778713 is an equidigital number, since it uses as much as digits as its factorization.

28778713 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10954.

The product of its digits is 131712, while the sum is 43.

The square root of 28778713 is about 5364.5794802575. The cubic root of 28778713 is about 306.4482338391.

The spelling of 28778713 in words is "twenty-eight million, seven hundred seventy-eight thousand, seven hundred thirteen".