1221001111111 has 8 divisors (see below), whose sum is σ = 1249464990224. Its totient is φ = 1192540345920.

The previous prime is 1221001111103. The next prime is 1221001111117. The reversal of 1221001111111 is 1111111001221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221001111111 - 2³ = 1221001111103 is a prime.

It is a Duffinian number.

1221001111111 is a modest number, since divided by 1111111 gives 122100 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 1221001111091 and 1221001111100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221001111117) 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 7 ways as a sum of consecutive naturals, for example, 24421 + ... + 1562881.

It is an arithmetic number, because the mean of its divisors is an integer number (156183123778).

Almost surely, 2^{1221001111111} is an apocalyptic number.

1221001111111 is a deficient number, since it is larger than the sum of its proper divisors (28463879113).

1221001111111 is a wasteful number, since it uses less digits than its factorization.

1221001111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556961.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 1221001111111 its reverse (1111111001221), we get a palindrome (2332112112332).

The spelling of 1221001111111 in words is "one trillion, two hundred twenty-one billion, one million, one hundred eleven thousand, one hundred eleven".