21722943 has 16 divisors (see below), whose sum is σ = 32688000. Its totient is φ = 12710880.

The previous prime is 21722933. The next prime is 21722963. The reversal of 21722943 is 34922712.

It is not a de Polignac number, because 21722943 - 2¹⁶ = 21657407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21722943.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10393 + ... + 12306.

It is an arithmetic number, because the mean of its divisors is an integer number (2043000).

Almost surely, 2^21722943 is an apocalyptic number.

21722943 is a deficient number, since it is larger than the sum of its proper divisors (10965057).

21722943 is a wasteful number, since it uses less digits than its factorization.

21722943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22742.

The product of its digits is 6048, while the sum is 30.

The square root of 21722943 is about 4660.7878089439. The cubic root of 21722943 is about 279.0227111174.

It can be divided in two parts, 2172 and 2943, that added together give a palindrome (5115).

The spelling of 21722943 in words is "twenty-one million, seven hundred twenty-two thousand, nine hundred forty-three".