21012011221220 has 12 divisors (see below), whose sum is σ = 44125223564604. Its totient is φ = 8404804488480.

The previous prime is 21012011221211. The next prime is 21012011221237. The reversal of 21012011221220 is 2212211021012.

It can be written as a sum of positive squares in 2 ways, for example, as 14215478796964 + 6796532424256 = 3770342^2 + 2607016^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525300280511 + ... + 525300280550.

It is an arithmetic number, because the mean of its divisors is an integer number (3677101963717).

Almost surely, 2^{21012011221220} is an apocalyptic number.

21012011221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012011221220 is an abundant number, since it is smaller than the sum of its proper divisors (23113212343384).

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

21012011221220 is a wasteful number, since it uses less digits than its factorization.

21012011221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050600561070 (or 1050600561068 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21012011221220 its reverse (2212211021012), we get a palindrome (23224222242232).

The spelling of 21012011221220 in words is "twenty-one trillion, twelve billion, eleven million, two hundred twenty-one thousand, two hundred twenty".