21485217 has 8 divisors (see below), whose sum is σ = 30850624. Its totient is φ = 13221648.

The previous prime is 21485213. The next prime is 21485221. The reversal of 21485217 is 71258412.

It is an interprime number because it is at equal distance from previous prime (21485213) and next prime (21485221).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21485217 - 2² = 21485213 is a prime.

It is a super-2 number, since 2×21485217² = 923229099074178, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21485213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 275413 + ... + 275490.

It is an arithmetic number, because the mean of its divisors is an integer number (3856328).

Almost surely, 2^21485217 is an apocalyptic number.

It is an amenable number.

21485217 is a deficient number, since it is larger than the sum of its proper divisors (9365407).

21485217 is a wasteful number, since it uses less digits than its factorization.

21485217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 550919.

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

The square root of 21485217 is about 4635.2148817504. The cubic root of 21485217 is about 278.0011429658.

The spelling of 21485217 in words is "twenty-one million, four hundred eighty-five thousand, two hundred seventeen".