21222550 has 12 divisors (see below), whose sum is σ = 39474036. Its totient is φ = 8489000.

The previous prime is 21222529. The next prime is 21222557. The reversal of 21222550 is 5522212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222557) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 212176 + ... + 212275.

It is an arithmetic number, because the mean of its divisors is an integer number (3289503).

Almost surely, 2^21222550 is an apocalyptic number.

21222550 is a deficient number, since it is larger than the sum of its proper divisors (18251486).

21222550 is a wasteful number, since it uses less digits than its factorization.

21222550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424463 (or 424458 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21222550 is about 4606.7938959758. The cubic root of 21222550 is about 276.8635958628.

Adding to 21222550 its reverse (5522212), we get a palindrome (26744762).

The spelling of 21222550 in words is "twenty-one million, two hundred twenty-two thousand, five hundred fifty".