21022224 has 40 divisors (see below), whose sum is σ = 54615552. Its totient is φ = 6967680.

The previous prime is 21022223. The next prime is 21022249. The reversal of 21022224 is 42222012.

It is a Cunningham number, because it is equal to 4585²-1.

It is not an unprimeable number, because it can be changed into a prime (21022223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8022 + ... + 10314.

Almost surely, 2^21022224 is an apocalyptic number.

21022224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21022224 is an abundant number, since it is smaller than the sum of its proper divisors (33593328).

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

21022224 is a wasteful number, since it uses less digits than its factorization.

21022224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2495 (or 2489 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 21022224 is about 4584.9998909487. Note that the first 3 decimals coincide. The cubic root of 21022224 is about 275.9897076607.

Adding to 21022224 its reverse (42222012), we get a palindrome (63244236).

The spelling of 21022224 in words is "twenty-one million, twenty-two thousand, two hundred twenty-four".