21522250 has 64 divisors (see below), whose sum is σ = 44478720. Its totient is φ = 7761600.

The previous prime is 21522223. The next prime is 21522251. The reversal of 21522250 is 5222512.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21522251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 109152 + ... + 109348.

It is an arithmetic number, because the mean of its divisors is an integer number (694980).

Almost surely, 2^21522250 is an apocalyptic number.

21522250 is an abundant number, since it is smaller than the sum of its proper divisors (22956470).

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

21522250 is a wasteful number, since it uses less digits than its factorization.

21522250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256 (or 246 counting only the distinct ones).

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

The square root of 21522250 is about 4639.2079065289. The cubic root of 21522250 is about 278.1607768646.

Adding to 21522250 its reverse (5222512), we get a palindrome (26744762).

The spelling of 21522250 in words is "twenty-one million, five hundred twenty-two thousand, two hundred fifty".