28999821 has 8 divisors (see below), whose sum is σ = 38691360. Its totient is φ = 19320752.

The previous prime is 28999801. The next prime is 28999829. The reversal of 28999821 is 12899982.

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

It is a cyclic number.

It is not a de Polignac number, because 28999821 - 2⁷ = 28999693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28999829) 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 7 ways as a sum of consecutive naturals, for example, 7066 + ... + 10388.

It is an arithmetic number, because the mean of its divisors is an integer number (4836420).

Almost surely, 2^28999821 is an apocalyptic number.

It is an amenable number.

28999821 is a deficient number, since it is larger than the sum of its proper divisors (9691539).

28999821 is a wasteful number, since it uses less digits than its factorization.

28999821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6235.

The product of its digits is 186624, while the sum is 48.

The square root of 28999821 is about 5385.1481873761. The cubic root of 28999821 is about 307.2310504469.

It can be divided in two parts, 2899 and 9821, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 28999821 in words is "twenty-eight million, nine hundred ninety-nine thousand, eight hundred twenty-one".