21222705 has 16 divisors (see below), whose sum is σ = 38807424. Its totient is φ = 9701760.

The previous prime is 21222697. The next prime is 21222739. The reversal of 21222705 is 50722212.

It is a happy number.

It is not a de Polignac number, because 21222705 - 2³ = 21222697 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100956 + ... + 101165.

It is an arithmetic number, because the mean of its divisors is an integer number (2425464).

Almost surely, 2^21222705 is an apocalyptic number.

It is an amenable number.

21222705 is a deficient number, since it is larger than the sum of its proper divisors (17584719).

21222705 is a wasteful number, since it uses less digits than its factorization.

21222705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202136.

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21222705 is about 4606.8107189248. The cubic root of 21222705 is about 276.8642698904.

Adding to 21222705 its reverse (50722212), we get a palindrome (71944917).

The spelling of 21222705 in words is "twenty-one million, two hundred twenty-two thousand, seven hundred five".