28217971 has 2 divisors, whose sum is σ = 28217972. Its totient is φ = 28217970.

The previous prime is 28217953. The next prime is 28217993. The reversal of 28217971 is 17971282.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28217971 - 2¹⁵ = 28185203 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28217971.

It is not a weakly prime, because it can be changed into another prime (28217171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14108985 + 14108986.

It is an arithmetic number, because the mean of its divisors is an integer number (14108986).

Almost surely, 2^28217971 is an apocalyptic number.

28217971 is a deficient number, since it is larger than the sum of its proper divisors (1).

28217971 is an equidigital number, since it uses as much as digits as its factorization.

28217971 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14112, while the sum is 37.

The square root of 28217971 is about 5312.0590169914. The cubic root of 28217971 is about 304.4448236104. Note that the first 3 decimals are identical.

The spelling of 28217971 in words is "twenty-eight million, two hundred seventeen thousand, nine hundred seventy-one".