28621905 has 32 divisors (see below), whose sum is σ = 50663424. Its totient is φ = 13706496.

The previous prime is 28621891. The next prime is 28621909. The reversal of 28621905 is 50912682.

It is not a de Polignac number, because 28621905 - 2⁴ = 28621889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28621909) 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 31 ways as a sum of consecutive naturals, for example, 5232 + ... + 9198.

It is an arithmetic number, because the mean of its divisors is an integer number (1583232).

Almost surely, 2^28621905 is an apocalyptic number.

It is an amenable number.

28621905 is a deficient number, since it is larger than the sum of its proper divisors (22041519).

28621905 is a wasteful number, since it uses less digits than its factorization.

28621905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4025.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 28621905 is about 5349.9443922344. The cubic root of 28621905 is about 305.8906333071.

The spelling of 28621905 in words is "twenty-eight million, six hundred twenty-one thousand, nine hundred five".