28820101 has 4 divisors (see below), whose sum is σ = 28912492. Its totient is φ = 28727712.

The previous prime is 28820063. The next prime is 28820119. The reversal of 28820101 is 10102882.

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 7568001 + 21252100 = 2751^2 + 4610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28820101 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 (28820401) 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, 45726 + ... + 46351.

It is an arithmetic number, because the mean of its divisors is an integer number (7228123).

Almost surely, 2^28820101 is an apocalyptic number.

It is an amenable number.

28820101 is a deficient number, since it is larger than the sum of its proper divisors (92391).

28820101 is an equidigital number, since it uses as much as digits as its factorization.

28820101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92390.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 28820101 is about 5368.4356194333. The cubic root of 28820101 is about 306.5950692706.

Adding to 28820101 its reverse (10102882), we get a palindrome (38922983).

The spelling of 28820101 in words is "twenty-eight million, eight hundred twenty thousand, one hundred one".