21024871 has 8 divisors (see below), whose sum is σ = 24519200. Its totient is φ = 18021024.

The previous prime is 21024859. The next prime is 21024889. The reversal of 21024871 is 17842012.

It is a happy number.

It is not a de Polignac number, because 21024871 - 2⁷ = 21024743 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 (21024271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30306 + ... + 30991.

It is an arithmetic number, because the mean of its divisors is an integer number (3064900).

Almost surely, 2^21024871 is an apocalyptic number.

21024871 is a deficient number, since it is larger than the sum of its proper divisors (3494329).

21024871 is an frugal number, since it uses more digits than its factorization.

21024871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61318 (or 61304 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21024871 is about 4585.2885405392. The cubic root of 21024871 is about 276.0012908642.

Adding to 21024871 its reverse (17842012), we get a palindrome (38866883).

The spelling of 21024871 in words is "twenty-one million, twenty-four thousand, eight hundred seventy-one".