1221111000100 has 72 divisors (see below), whose sum is σ = 2659212049536. Its totient is φ = 486713040000.

The previous prime is 1221111000089. The next prime is 1221111000107. The reversal of 1221111000100 is 10001111221.

It is a super-2 number, since 2×1221111000100² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (1221111000107) 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 23 ways as a sum of consecutive naturals, for example, 70858485 + ... + 70875715.

It is an arithmetic number, because the mean of its divisors is an integer number (36933500688).

Almost surely, 2^{1221111000100} is an apocalyptic number.

1221111000100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221111000100 is an abundant number, since it is smaller than the sum of its proper divisors (1438101049436).

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

1221111000100 is a wasteful number, since it uses less digits than its factorization.

1221111000100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19717 (or 19710 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 1221111000100 its reverse (10001111221), we get a palindrome (1231112111321).

It can be divided in two parts, 122111 and 1000100, that added together give a palindrome (1122211).

The spelling of 1221111000100 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred", and thus it is an aban number.