1001211221220 has 96 divisors (see below), whose sum is σ = 3207281930496. Its totient is φ = 228604992000.

The previous prime is 1001211221209. The next prime is 1001211221261. The reversal of 1001211221220 is 221221121001.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1001211221220.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 871431 + ... + 1661870.

It is an arithmetic number, because the mean of its divisors is an integer number (33409186776).

Almost surely, 2^{1001211221220} is an apocalyptic number.

1001211221220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1001211221220 is an abundant number, since it is smaller than the sum of its proper divisors (2206070709276).

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

1001211221220 is a wasteful number, since it uses less digits than its factorization.

1001211221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2534261 (or 2534259 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 1001211221220 its reverse (221221121001), we get a palindrome (1222432342221).

The spelling of 1001211221220 in words is "one trillion, one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred twenty".