28866621 has 8 divisors (see below), whose sum is σ = 43987264. Its totient is φ = 16495200.

The previous prime is 28866599. The next prime is 28866637. The reversal of 28866621 is 12666882.

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

It is not a de Polignac number, because 28866621 - 2⁵ = 28866589 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 28866621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28867621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 687280 + ... + 687321.

It is an arithmetic number, because the mean of its divisors is an integer number (5498408).

Almost surely, 2^28866621 is an apocalyptic number.

28866621 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28866621 is a deficient number, since it is larger than the sum of its proper divisors (15120643).

28866621 is a wasteful number, since it uses less digits than its factorization.

28866621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1374611.

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

The square root of 28866621 is about 5372.7666057628. The cubic root of 28866621 is about 306.7599441888.

The spelling of 28866621 in words is "twenty-eight million, eight hundred sixty-six thousand, six hundred twenty-one".