1212212021220 has 144 divisors (see below), whose sum is σ = 3813815114928. Its totient is φ = 311405644800.

The previous prime is 1212212021203. The next prime is 1212212021233. The reversal of 1212212021220 is 221202122121.

It is a happy number.

1212212021220 is a `hidden beast` number, since 1 + 21 + 221 + 202 + 1 + 220 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 11241512676 + 1200970508544 = 106026^2 + 1095888^2 .

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 = 1212212021193 and 1212212021202.

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 47 ways as a sum of consecutive naturals, for example, 228399 + ... + 1573718.

It is an arithmetic number, because the mean of its divisors is an integer number (26484827187).

Almost surely, 2^{1212212021220} is an apocalyptic number.

1212212021220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1212212021220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1906907557464).

1212212021220 is an abundant number, since it is smaller than the sum of its proper divisors (2601603093708).

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

1212212021220 is a wasteful number, since it uses less digits than its factorization.

1212212021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1802270 (or 1802265 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1212212021220 its reverse (221202122121), we get a palindrome (1433414143341).

The spelling of 1212212021220 in words is "one trillion, two hundred twelve billion, two hundred twelve million, twenty-one thousand, two hundred twenty".