21722838 has 16 divisors (see below), whose sum is σ = 46001520. Its totient is φ = 6814976.

The previous prime is 21722837. The next prime is 21722851. The reversal of 21722838 is 83822712.

It is a junction number, because it is equal to n+sod(n) for n = 21722799 and 21722808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722837) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106383 + ... + 106586.

It is an arithmetic number, because the mean of its divisors is an integer number (2875095).

Almost surely, 2^21722838 is an apocalyptic number.

21722838 is an abundant number, since it is smaller than the sum of its proper divisors (24278682).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21722838 is a wasteful number, since it uses less digits than its factorization.

21722838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212991.

The product of its digits is 10752, while the sum is 33.

The square root of 21722838 is about 4660.7765447402. The cubic root of 21722838 is about 279.0222615554.

The spelling of 21722838 in words is "twenty-one million, seven hundred twenty-two thousand, eight hundred thirty-eight".