28821617 has 4 divisors (see below), whose sum is σ = 31441776. Its totient is φ = 26201460.

The previous prime is 28821607. The next prime is 28821629. The reversal of 28821617 is 71612882.

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 28821617 - 2⁴ = 28821601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28821607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1310063 + ... + 1310084.

It is an arithmetic number, because the mean of its divisors is an integer number (7860444).

Almost surely, 2^28821617 is an apocalyptic number.

It is an amenable number.

28821617 is a deficient number, since it is larger than the sum of its proper divisors (2620159).

28821617 is a wasteful number, since it uses less digits than its factorization.

28821617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2620158.

The product of its digits is 10752, while the sum is 35.

The square root of 28821617 is about 5368.5768132718. The cubic root of 28821617 is about 306.6004450321.

The spelling of 28821617 in words is "twenty-eight million, eight hundred twenty-one thousand, six hundred seventeen".