21162220 has 36 divisors (see below), whose sum is σ = 45501120. Its totient is φ = 8267488.

The previous prime is 21162217. The next prime is 21162247. The reversal of 21162220 is 2226112.

It is a junction number, because it is equal to n+sod(n) for n = 21162194 and 21162203.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43941 + ... + 44419.

It is an arithmetic number, because the mean of its divisors is an integer number (1263920).

Almost surely, 2^21162220 is an apocalyptic number.

21162220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21162220 is an abundant number, since it is smaller than the sum of its proper divisors (24338900).

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

21162220 is a wasteful number, since it uses less digits than its factorization.

21162220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582 (or 533 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21162220 is about 4600.2412980191. The cubic root of 21162220 is about 276.6009973009.

Adding to 21162220 its reverse (2226112), we get a palindrome (23388332).

The spelling of 21162220 in words is "twenty-one million, one hundred sixty-two thousand, two hundred twenty".