28621969 has 4 divisors (see below), whose sum is σ = 28966896. Its totient is φ = 28277044.

The previous prime is 28621909. The next prime is 28621991. The reversal of 28621969 is 96912682.

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 28621969 - 2⁷ = 28621841 is a prime.

It is a super-2 number, since 2×28621969² = 1638434218873922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28621909) 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, 172339 + ... + 172504.

It is an arithmetic number, because the mean of its divisors is an integer number (7241724).

Almost surely, 2^28621969 is an apocalyptic number.

It is an amenable number.

28621969 is a deficient number, since it is larger than the sum of its proper divisors (344927).

28621969 is an equidigital number, since it uses as much as digits as its factorization.

28621969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344926.

The product of its digits is 93312, while the sum is 43.

The square root of 28621969 is about 5349.9503736016. The cubic root of 28621969 is about 305.8908613025.

The spelling of 28621969 in words is "twenty-eight million, six hundred twenty-one thousand, nine hundred sixty-nine".