28021535 has 4 divisors (see below), whose sum is σ = 33625848. Its totient is φ = 22417224.

The previous prime is 28021531. The next prime is 28021579. The reversal of 28021535 is 53512082.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28021535 - 2² = 28021531 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 (28021531) 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, 2802149 + ... + 2802158.

It is an arithmetic number, because the mean of its divisors is an integer number (8406462).

Almost surely, 2^28021535 is an apocalyptic number.

28021535 is a deficient number, since it is larger than the sum of its proper divisors (5604313).

28021535 is an equidigital number, since it uses as much as digits as its factorization.

28021535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5604312.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 28021535 is about 5293.5370972536. The cubic root of 28021535 is about 303.7367259804.

The spelling of 28021535 in words is "twenty-eight million, twenty-one thousand, five hundred thirty-five".