1221220121004 has 96 divisors (see below), whose sum is σ = 3439848968640. Its totient is φ = 372434678784.

The previous prime is 1221220121003. The next prime is 1221220121039. The reversal of 1221220121004 is 4001210221221.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (1221220121003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3690087 + ... + 4007390.

It is an arithmetic number, because the mean of its divisors is an integer number (35831760090).

Almost surely, 2^{1221220121004} is an apocalyptic number.

It is an amenable number.

1221220121004 is an abundant number, since it is smaller than the sum of its proper divisors (2218628847636).

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

1221220121004 is a wasteful number, since it uses less digits than its factorization.

1221220121004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7697616 (or 7697608 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221220121004 its reverse (4001210221221), we get a palindrome (5222430342225).

The spelling of 1221220121004 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, four".