21822156 has 96 divisors (see below), whose sum is σ = 59924480. Its totient is φ = 6858432.

The previous prime is 21822149. The next prime is 21822173. The reversal of 21822156 is 65122812.

It is a happy number.

It is a super-4 number, since 4×21822156⁴ (a number of 30 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 171765 + ... + 171891.

Almost surely, 2^21822156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21822156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29962240).

21822156 is an abundant number, since it is smaller than the sum of its proper divisors (38102324).

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

21822156 is a wasteful number, since it uses less digits than its factorization.

21822156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 212 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21822156 is about 4671.4190563468. The cubic root of 21822156 is about 279.4468501294.

Adding to 21822156 its reverse (65122812), we get a palindrome (86944968).

The spelling of 21822156 in words is "twenty-one million, eight hundred twenty-two thousand, one hundred fifty-six".