21479217 has 8 divisors (see below), whose sum is σ = 29884224. Its totient is φ = 13696848.

The previous prime is 21479209. The next prime is 21479221. The reversal of 21479217 is 71297412.

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

It is not a de Polignac number, because 21479217 - 2³ = 21479209 is a prime.

It is a super-3 number, since 3×21479217³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (21479917) 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, 155578 + ... + 155715.

It is an arithmetic number, because the mean of its divisors is an integer number (3735528).

Almost surely, 2^21479217 is an apocalyptic number.

It is an amenable number.

21479217 is a deficient number, since it is larger than the sum of its proper divisors (8405007).

21479217 is a wasteful number, since it uses less digits than its factorization.

21479217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311319.

The product of its digits is 7056, while the sum is 33.

The square root of 21479217 is about 4634.5676173727. The cubic root of 21479217 is about 277.9752621916.

The spelling of 21479217 in words is "twenty-one million, four hundred seventy-nine thousand, two hundred seventeen".