1221011001210 has 384 divisors, whose sum is σ = 4071551565312. Its totient is φ = 227867904000.

The previous prime is 1221011001187. The next prime is 1221011001211. The reversal of 1221011001210 is 121001101221.

It is not an unprimeable number, because it can be changed into a prime (1221011001211) by changing a digit.

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 191 ways as a sum of consecutive naturals, for example, 12172260 + ... + 12272160.

It is an arithmetic number, because the mean of its divisors is an integer number (10602998868).

Almost surely, 2^{1221011001210} is an apocalyptic number.

1221011001210 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221011001210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2035775782656).

1221011001210 is an abundant number, since it is smaller than the sum of its proper divisors (2850540564102).

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

1221011001210 is a wasteful number, since it uses less digits than its factorization.

1221011001210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99990 (or 99979 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 1221011001210 its reverse (121001101221), we get a palindrome (1342012102431).

The spelling of 1221011001210 in words is "one trillion, two hundred twenty-one billion, eleven million, one thousand, two hundred ten".