28167621 has 4 divisors (see below), whose sum is σ = 37556832. Its totient is φ = 18778412.

The previous prime is 28167599. The next prime is 28167631. The reversal of 28167621 is 12676182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28167621 - 2⁷ = 28167493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28167631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4694601 + ... + 4694606.

It is an arithmetic number, because the mean of its divisors is an integer number (9389208).

Almost surely, 2^28167621 is an apocalyptic number.

It is an amenable number.

28167621 is a deficient number, since it is larger than the sum of its proper divisors (9389211).

28167621 is an equidigital number, since it uses as much as digits as its factorization.

28167621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9389210.

The product of its digits is 8064, while the sum is 33.

The square root of 28167621 is about 5307.3176841037. The cubic root of 28167621 is about 304.2636397459.

The spelling of 28167621 in words is "twenty-eight million, one hundred sixty-seven thousand, six hundred twenty-one".