1221212111020 has 96 divisors (see below), whose sum is σ = 2948229881856. Its totient is φ = 420563616000.

The previous prime is 1221212111003. The next prime is 1221212111023. The reversal of 1221212111020 is 201112121221.

It is a junction number, because it is equal to n+sod(n) for n = 1221212110985 and 1221212111003.

It is not an unprimeable number, because it can be changed into a prime (1221212111023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 683724 + ... + 1705843.

It is an arithmetic number, because the mean of its divisors is an integer number (30710727936).

Almost surely, 2^{1221212111020} is an apocalyptic number.

1221212111020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221212111020 is an abundant number, since it is smaller than the sum of its proper divisors (1727017770836).

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

1221212111020 is a wasteful number, since it uses less digits than its factorization.

1221212111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2389711 (or 2389709 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221212111020 its reverse (201112121221), we get a palindrome (1422324232241).

The spelling of 1221212111020 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, one hundred eleven thousand, twenty".