21231722 has 8 divisors (see below), whose sum is σ = 31922436. Its totient is φ = 10590912.

The previous prime is 21231719. The next prime is 21231731. The reversal of 21231722 is 22713212.

It can be written as a sum of positive squares in 2 ways, for example, as 18412681 + 2819041 = 4291^2 + 1679^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21231694 and 21231703.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11393 + ... + 13124.

Almost surely, 2^21231722 is an apocalyptic number.

21231722 is a deficient number, since it is larger than the sum of its proper divisors (10690714).

21231722 is a wasteful number, since it uses less digits than its factorization.

21231722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24952.

The product of its digits is 336, while the sum is 20.

The square root of 21231722 is about 4607.7892746956. The cubic root of 21231722 is about 276.9034752547.

Adding to 21231722 its reverse (22713212), we get a palindrome (43944934).

The spelling of 21231722 in words is "twenty-one million, two hundred thirty-one thousand, seven hundred twenty-two".