21949224 has 64 divisors (see below), whose sum is σ = 60756480. Its totient is φ = 6552000.

The previous prime is 21949223. The next prime is 21949229. The reversal of 21949224 is 42294912.

It is a Cunningham number, because it is equal to 4685²-1.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21949223) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 18159 + ... + 19329.

It is an arithmetic number, because the mean of its divisors is an integer number (949320).

Almost surely, 2^21949224 is an apocalyptic number.

21949224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21949224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30378240).

21949224 is an abundant number, since it is smaller than the sum of its proper divisors (38807256).

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

21949224 is a wasteful number, since it uses less digits than its factorization.

21949224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1262 (or 1258 counting only the distinct ones).

The product of its digits is 10368, while the sum is 33.

The square root of 21949224 is about 4684.9998932764. Note that the first 3 decimals coincide. The cubic root of 21949224 is about 279.9881967814.

The spelling of 21949224 in words is "twenty-one million, nine hundred forty-nine thousand, two hundred twenty-four".