1221021001218 has 64 divisors (see below), whose sum is σ = 2593990656000. Its totient is φ = 382074336000.

The previous prime is 1221021001217. The next prime is 1221021001231. The reversal of 1221021001218 is 8121001201221.

It is a junction number, because it is equal to n+sod(n) for n = 1221021001194 and 1221021001203.

It is not an unprimeable number, because it can be changed into a prime (1221021001217) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 61810843 + ... + 61830593.

It is an arithmetic number, because the mean of its divisors is an integer number (40531104000).

Almost surely, 2^{1221021001218} is an apocalyptic number.

1221021001218 is an abundant number, since it is smaller than the sum of its proper divisors (1372969654782).

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

1221021001218 is a wasteful number, since it uses less digits than its factorization.

1221021001218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24687.

The product of its (nonzero) digits is 128, while the sum is 21.

Adding to 1221021001218 its reverse (8121001201221), we get a palindrome (9342022202439).

The spelling of 1221021001218 in words is "one trillion, two hundred twenty-one billion, twenty-one million, one thousand, two hundred eighteen".