21522220 has 12 divisors (see below), whose sum is σ = 45196704. Its totient is φ = 8608880.

The previous prime is 21522217. The next prime is 21522223. The reversal of 21522220 is 2222512.

It is an interprime number because it is at equal distance from previous prime (21522217) and next prime (21522223).

It is a junction number, because it is equal to n+sod(n) for n = 21522194 and 21522203.

It is not an unprimeable number, because it can be changed into a prime (21522223) 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 3 ways as a sum of consecutive naturals, for example, 538036 + ... + 538075.

It is an arithmetic number, because the mean of its divisors is an integer number (3766392).

Almost surely, 2^21522220 is an apocalyptic number.

21522220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21522220 is an abundant number, since it is smaller than the sum of its proper divisors (23674484).

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

21522220 is a wasteful number, since it uses less digits than its factorization.

21522220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076120 (or 1076118 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21522220 is about 4639.2046732172. The cubic root of 21522220 is about 278.1606476212.

Adding to 21522220 its reverse (2222512), we get a palindrome (23744732).

The spelling of 21522220 in words is "twenty-one million, five hundred twenty-two thousand, two hundred twenty".