1221012220100 has 18 divisors (see below), whose sum is σ = 2649596517834. Its totient is φ = 488404888000.

The previous prime is 1221012220081. The next prime is 1221012220139. The reversal of 1221012220100 is 10222101221.

It can be written as a sum of positive squares in 3 ways, for example, as 415581358336 + 805430861764 = 644656^2 + 897458^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6105061001 + ... + 6105061200.

Almost surely, 2^{1221012220100} is an apocalyptic number.

1221012220100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012220100 is an abundant number, since it is smaller than the sum of its proper divisors (1428584297734).

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

1221012220100 is a wasteful number, since it uses less digits than its factorization.

1221012220100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12210122215 (or 12210122208 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 1221012220100 its reverse (10222101221), we get a palindrome (1231234321321).

The spelling of 1221012220100 in words is "one trillion, two hundred twenty-one billion, twelve million, two hundred twenty thousand, one hundred".