28405002121 has 4 divisors (see below), whose sum is σ = 29321292544. Its totient is φ = 27488711700.

The previous prime is 28405002079. The next prime is 28405002127. The reversal of 28405002121 is 12120050482.

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 28405002121 - 2²⁷ = 28270784393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28405002127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 458145165 + ... + 458145226.

It is an arithmetic number, because the mean of its divisors is an integer number (7330323136).

Almost surely, 2^28405002121 is an apocalyptic number.

It is an amenable number.

28405002121 is a deficient number, since it is larger than the sum of its proper divisors (916290423).

28405002121 is an equidigital number, since it uses as much as digits as its factorization.

28405002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916290422.

The product of its (nonzero) digits is 1280, while the sum is 25.

The spelling of 28405002121 in words is "twenty-eight billion, four hundred five million, two thousand, one hundred twenty-one".