28217771 has 4 divisors (see below), whose sum is σ = 28281912. Its totient is φ = 28153632.

The previous prime is 28217741. The next prime is 28217779. The reversal of 28217771 is 17771282.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17771282 = 2 ⋅8885641.

It is a cyclic number.

It is not a de Polignac number, because 28217771 - 2¹⁴ = 28201387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28217779) 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, 31406 + ... + 32291.

It is an arithmetic number, because the mean of its divisors is an integer number (7070478).

Almost surely, 2^28217771 is an apocalyptic number.

28217771 is a deficient number, since it is larger than the sum of its proper divisors (64141).

28217771 is an equidigital number, since it uses as much as digits as its factorization.

28217771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64140.

The product of its digits is 10976, while the sum is 35.

The square root of 28217771 is about 5312.0401918660. The cubic root of 28217771 is about 304.4441043393. Note that the first 3 decimals are identical.

The spelling of 28217771 in words is "twenty-eight million, two hundred seventeen thousand, seven hundred seventy-one".