21000212122220 has 24 divisors (see below), whose sum is σ = 44115859923408. Its totient is φ = 8397148760000.

The previous prime is 21000212122189. The next prime is 21000212122249. The reversal of 21000212122220 is 2222121200012.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 183446906 + ... + 183561345.

It is an arithmetic number, because the mean of its divisors is an integer number (1838160830142).

Almost surely, 2^{21000212122220} is an apocalyptic number.

21000212122220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000212122220 is an abundant number, since it is smaller than the sum of its proper divisors (23115647801188).

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

21000212122220 is a wasteful number, since it uses less digits than its factorization.

21000212122220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367011121 (or 367011119 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21000212122220 its reverse (2222121200012), we get a palindrome (23222333322232).

The spelling of 21000212122220 in words is "twenty-one trillion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty".