21223220220 has 72 divisors (see below), whose sum is σ = 66597017760. Its totient is φ = 5464368000.

The previous prime is 21223220209. The next prime is 21223220243. The reversal of 21223220220 is 2202232212.

21223220220 is a `hidden beast` number, since 2 + 1 + 223 + 220 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21223220193 and 21223220202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2027656 + ... + 2038095.

It is an arithmetic number, because the mean of its divisors is an integer number (924958580).

Almost surely, 2^21223220220 is an apocalyptic number.

21223220220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21223220220 is an abundant number, since it is smaller than the sum of its proper divisors (45373797540).

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

21223220220 is a wasteful number, since it uses less digits than its factorization.

21223220220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4065795 (or 4065790 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21223220220 its reverse (2202232212), we get a palindrome (23425452432).

The spelling of 21223220220 in words is "twenty-one billion, two hundred twenty-three million, two hundred twenty thousand, two hundred twenty".