28921863 has 4 divisors (see below), whose sum is σ = 38562488. Its totient is φ = 19281240.

The previous prime is 28921861. The next prime is 28921877. The reversal of 28921863 is 36812982.

It is a happy number.

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

It is not a de Polignac number, because 28921863 - 2¹ = 28921861 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 (28921861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4820308 + ... + 4820313.

It is an arithmetic number, because the mean of its divisors is an integer number (9640622).

Almost surely, 2^28921863 is an apocalyptic number.

28921863 is a deficient number, since it is larger than the sum of its proper divisors (9640625).

28921863 is an equidigital number, since it uses as much as digits as its factorization.

28921863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9640624.

The product of its digits is 41472, while the sum is 39.

The square root of 28921863 is about 5377.9050753988. The cubic root of 28921863 is about 306.9555014780.

The spelling of 28921863 in words is "twenty-eight million, nine hundred twenty-one thousand, eight hundred sixty-three".