28021191 has 8 divisors (see below), whose sum is σ = 40758144. Its totient is φ = 16982520.

The previous prime is 28021187. The next prime is 28021193. The reversal of 28021191 is 19112082.

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

It is not a de Polignac number, because 28021191 - 2² = 28021187 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021193) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 424531 + ... + 424596.

It is an arithmetic number, because the mean of its divisors is an integer number (5094768).

Almost surely, 2^28021191 is an apocalyptic number.

28021191 is a deficient number, since it is larger than the sum of its proper divisors (12736953).

28021191 is a wasteful number, since it uses less digits than its factorization.

28021191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849141.

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 28021191 is about 5293.5046047019. The cubic root of 28021191 is about 303.7354830570.

It can be divided in two parts, 2802 and 1191, that added together give a palindrome (3993).

The spelling of 28021191 in words is "twenty-eight million, twenty-one thousand, one hundred ninety-one".