28139693 has 4 divisors (see below), whose sum is σ = 28328700. Its totient is φ = 27950688.

The previous prime is 28139689. The next prime is 28139707. The reversal of 28139693 is 39693182.

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 7327849 + 20811844 = 2707^2 + 4562^2 .

It is a cyclic number.

It is not a de Polignac number, because 28139693 - 2² = 28139689 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 28139693.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28139633) 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, 94280 + ... + 94577.

It is an arithmetic number, because the mean of its divisors is an integer number (7082175).

Almost surely, 2^28139693 is an apocalyptic number.

It is an amenable number.

28139693 is a deficient number, since it is larger than the sum of its proper divisors (189007).

28139693 is a wasteful number, since it uses less digits than its factorization.

28139693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189006.

The product of its digits is 69984, while the sum is 41.

The square root of 28139693 is about 5304.6859473488. The cubic root of 28139693 is about 304.1630480669.

The spelling of 28139693 in words is "twenty-eight million, one hundred thirty-nine thousand, six hundred ninety-three".