1221355411212 has 192 divisors, whose sum is σ = 3174396825600. Its totient is φ = 363986472960.

The previous prime is 1221355411189. The next prime is 1221355411247. The reversal of 1221355411212 is 2121145531221.

It is a self number, because there is not a number n which added to its sum of digits gives 1221355411212.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 45907498 + ... + 45934094.

It is an arithmetic number, because the mean of its divisors is an integer number (16533316800).

Almost surely, 2^{1221355411212} is an apocalyptic number.

1221355411212 is a gapful number since it is divisible by the number (12) 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 1221355411212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1587198412800).

1221355411212 is an abundant number, since it is smaller than the sum of its proper divisors (1953041414388).

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

1221355411212 is a wasteful number, since it uses less digits than its factorization.

1221355411212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26816 (or 26814 counting only the distinct ones).

The product of its digits is 4800, while the sum is 30.

The spelling of 1221355411212 in words is "one trillion, two hundred twenty-one billion, three hundred fifty-five million, four hundred eleven thousand, two hundred twelve".