28638813 has 8 divisors (see below), whose sum is σ = 43640128. Its totient is φ = 16365024.

The previous prime is 28638809. The next prime is 28638821. The reversal of 28638813 is 31883682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28638813 - 2² = 28638809 is a prime.

It is a super-2 number, since 2×28638813² = 1640363220097938, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28638803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 681856 + ... + 681897.

It is an arithmetic number, because the mean of its divisors is an integer number (5455016).

Almost surely, 2^28638813 is an apocalyptic number.

It is an amenable number.

28638813 is a deficient number, since it is larger than the sum of its proper divisors (15001315).

28638813 is a wasteful number, since it uses less digits than its factorization.

28638813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1363763.

The product of its digits is 55296, while the sum is 39.

The square root of 28638813 is about 5351.5243622729. The cubic root of 28638813 is about 305.9508550235.

The spelling of 28638813 in words is "twenty-eight million, six hundred thirty-eight thousand, eight hundred thirteen".