28078657 has 4 divisors (see below), whose sum is σ = 28094596. Its totient is φ = 28062720.

The previous prime is 28078649. The next prime is 28078691. The reversal of 28078657 is 75687082.

It is a happy number.

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 20466576 + 7612081 = 4524^2 + 2759^2 .

It is a cyclic number.

It is not a de Polignac number, because 28078657 - 2³ = 28078649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28078627) 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, 4944 + ... + 8977.

It is an arithmetic number, because the mean of its divisors is an integer number (7023649).

Almost surely, 2^28078657 is an apocalyptic number.

It is an amenable number.

28078657 is a deficient number, since it is larger than the sum of its proper divisors (15939).

28078657 is a wasteful number, since it uses less digits than its factorization.

28078657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15938.

The product of its (nonzero) digits is 188160, while the sum is 43.

The square root of 28078657 is about 5298.9297976101. The cubic root of 28078657 is about 303.9429753669.

The spelling of 28078657 in words is "twenty-eight million, seventy-eight thousand, six hundred fifty-seven".