28219001 has 4 divisors (see below), whose sum is σ = 29192100. Its totient is φ = 27245904.

The previous prime is 28218991. The next prime is 28219007. The reversal of 28219001 is 10091282.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8549776 + 19669225 = 2924^2 + 4435^2 .

It is a cyclic number.

It is not a de Polignac number, because 28219001 - 2⁶ = 28218937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28219007) 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, 486506 + ... + 486563.

It is an arithmetic number, because the mean of its divisors is an integer number (7298025).

Almost surely, 2^28219001 is an apocalyptic number.

It is an amenable number.

28219001 is a deficient number, since it is larger than the sum of its proper divisors (973099).

28219001 is an equidigital number, since it uses as much as digits as its factorization.

28219001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973098.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 28219001 is about 5312.1559653308. The cubic root of 28219001 is about 304.4485278024.

The spelling of 28219001 in words is "twenty-eight million, two hundred nineteen thousand, one".