28263621 has 16 divisors (see below), whose sum is σ = 39800000. Its totient is φ = 17791488.

The previous prime is 28263617. The next prime is 28263623. The reversal of 28263621 is 12636282.

It is not a de Polignac number, because 28263621 - 2² = 28263617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28263623) 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 15 ways as a sum of consecutive naturals, for example, 22005 + ... + 23253.

It is an arithmetic number, because the mean of its divisors is an integer number (2487500).

Almost surely, 2^28263621 is an apocalyptic number.

It is an amenable number.

28263621 is a deficient number, since it is larger than the sum of its proper divisors (11536379).

28263621 is a wasteful number, since it uses less digits than its factorization.

28263621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1668.

The product of its digits is 6912, while the sum is 30.

The square root of 28263621 is about 5316.3541078450. The cubic root of 28263621 is about 304.6089083872.

It can be divided in two parts, 282 and 63621, that added together give a triangular number (63903 = T₃₅₇).

The spelling of 28263621 in words is "twenty-eight million, two hundred sixty-three thousand, six hundred twenty-one".