21248517 has 16 divisors (see below), whose sum is σ = 30018560. Its totient is φ = 13331952.

The previous prime is 21248501. The next prime is 21248519. The reversal of 21248517 is 71584212.

It is not a de Polignac number, because 21248517 - 2⁴ = 21248501 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 (21248519) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8148 + ... + 10434.

It is an arithmetic number, because the mean of its divisors is an integer number (1876160).

Almost surely, 2^21248517 is an apocalyptic number.

It is an amenable number.

21248517 is a deficient number, since it is larger than the sum of its proper divisors (8770043).

21248517 is a wasteful number, since it uses less digits than its factorization.

21248517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2472.

The product of its digits is 4480, while the sum is 30.

The square root of 21248517 is about 4609.6113719054. The cubic root of 21248517 is about 276.9764693049.

The spelling of 21248517 in words is "twenty-one million, two hundred forty-eight thousand, five hundred seventeen".