21722273 has 4 divisors (see below), whose sum is σ = 21739200. Its totient is φ = 21705348.

The previous prime is 21722269. The next prime is 21722279. The reversal of 21722273 is 37222712.

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 21722273 - 2² = 21722269 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21722279) 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, 6365 + ... + 9162.

It is an arithmetic number, because the mean of its divisors is an integer number (5434800).

Almost surely, 2^21722273 is an apocalyptic number.

It is an amenable number.

21722273 is a deficient number, since it is larger than the sum of its proper divisors (16927).

21722273 is a wasteful number, since it uses less digits than its factorization.

21722273 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16926.

The product of its digits is 2352, while the sum is 26.

The square root of 21722273 is about 4660.7159321289. The cubic root of 21722273 is about 279.0198424585.

Adding to 21722273 its reverse (37222712), we get a palindrome (58944985).

The spelling of 21722273 in words is "twenty-one million, seven hundred twenty-two thousand, two hundred seventy-three".