21480217 has 4 divisors (see below), whose sum is σ = 23432976. Its totient is φ = 19527460.

The previous prime is 21480209. The next prime is 21480223. The reversal of 21480217 is 71208412.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21480217 - 2³ = 21480209 is a prime.

It is a super-2 number, since 2×21480217² = 922799444734178, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21480191 and 21480200.

It is not an unprimeable number, because it can be changed into a prime (21480227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 976363 + ... + 976384.

It is an arithmetic number, because the mean of its divisors is an integer number (5858244).

Almost surely, 2^21480217 is an apocalyptic number.

It is an amenable number.

21480217 is a deficient number, since it is larger than the sum of its proper divisors (1952759).

21480217 is a wasteful number, since it uses less digits than its factorization.

21480217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1952758.

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

The square root of 21480217 is about 4634.6755010464. The cubic root of 21480217 is about 277.9795759886.

Adding to 21480217 its reverse (71208412), we get a palindrome (92688629).

The spelling of 21480217 in words is "twenty-one million, four hundred eighty thousand, two hundred seventeen".