21212223122220 has 96 divisors (see below), whose sum is σ = 64549828136640. Its totient is φ = 5173566888960.

The previous prime is 21212223122179. The next prime is 21212223122221. The reversal of 21212223122220 is 2222132221212.

It is not an unprimeable number, because it can be changed into a prime (21212223122221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 124663411 + ... + 124833450.

It is an arithmetic number, because the mean of its divisors is an integer number (672394043090).

Almost surely, 2^{21212223122220} is an apocalyptic number.

21212223122220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212223122220 is an abundant number, since it is smaller than the sum of its proper divisors (43337605014420).

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

21212223122220 is a wasteful number, since it uses less digits than its factorization.

21212223122220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249496995 (or 249496993 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21212223122220 its reverse (2222132221212), we get a palindrome (23434355343432).

The spelling of 21212223122220 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty-three million, one hundred twenty-two thousand, two hundred twenty".