21250271 has 6 divisors (see below), whose sum is σ = 24719760. Its totient is φ = 18214476.

The previous prime is 21250253. The next prime is 21250279. The reversal of 21250271 is 17205212.

It is a de Polignac number, because none of the positive numbers 2^k-21250271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216791 + ... + 216888.

It is an arithmetic number, because the mean of its divisors is an integer number (4119960).

Almost surely, 2^21250271 is an apocalyptic number.

21250271 is a deficient number, since it is larger than the sum of its proper divisors (3469489).

21250271 is an equidigital number, since it uses as much as digits as its factorization.

21250271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433693 (or 433686 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21250271 is about 4609.8016226298. The cubic root of 21250271 is about 276.9840902816.

Adding to 21250271 its reverse (17205212), we get a palindrome (38455483).

The spelling of 21250271 in words is "twenty-one million, two hundred fifty thousand, two hundred seventy-one".