28219481 has 4 divisors (see below), whose sum is σ = 28875792. Its totient is φ = 27563172.

The previous prime is 28219463. The next prime is 28219487. The reversal of 28219481 is 18491282.

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 de Polignac number, because none of the positive numbers 2^k-28219481 is a prime.

It is a super-2 number, since 2×28219481² = 1592678215818722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28219487) 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 3 ways as a sum of consecutive naturals, for example, 328091 + ... + 328176.

It is an arithmetic number, because the mean of its divisors is an integer number (7218948).

Almost surely, 2^28219481 is an apocalyptic number.

It is an amenable number.

28219481 is a deficient number, since it is larger than the sum of its proper divisors (656311).

28219481 is an equidigital number, since it uses as much as digits as its factorization.

28219481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656310.

The product of its digits is 9216, while the sum is 35.

The square root of 28219481 is about 5312.2011445351. The cubic root of 28219481 is about 304.4502539971.

The spelling of 28219481 in words is "twenty-eight million, two hundred nineteen thousand, four hundred eighty-one".