28921001 has 4 divisors (see below), whose sum is σ = 29141904. Its totient is φ = 28700100.

The previous prime is 28920989. The next prime is 28921007. The reversal of 28921001 is 10012982.

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 cyclic number.

It is not a de Polignac number, because 28921001 - 2¹⁸ = 28658857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28921007) 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, 110255 + ... + 110516.

It is an arithmetic number, because the mean of its divisors is an integer number (7285476).

Almost surely, 2^28921001 is an apocalyptic number.

It is an amenable number.

28921001 is a deficient number, since it is larger than the sum of its proper divisors (220903).

28921001 is a wasteful number, since it uses less digits than its factorization.

28921001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220902.

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

The square root of 28921001 is about 5377.8249320706. The cubic root of 28921001 is about 306.9524519018.

Adding to 28921001 its reverse (10012982), we get a palindrome (38933983).

The spelling of 28921001 in words is "twenty-eight million, nine hundred twenty-one thousand, one".