1221000001111 has 4 divisors (see below), whose sum is σ = 1332000001224. Its totient is φ = 1110000001000.

The previous prime is 1221000001063. The next prime is 1221000001171. The reversal of 1221000001111 is 1111000001221.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-1221000001111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221000001171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55500000040 + ... + 55500000061.

It is an arithmetic number, because the mean of its divisors is an integer number (333000000306).

Almost surely, 2^{1221000001111} is an apocalyptic number.

1221000001111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221000001111 is a deficient number, since it is larger than the sum of its proper divisors (111000000113).

1221000001111 is a wasteful number, since it uses less digits than its factorization.

1221000001111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111000000112.

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

Adding to 1221000001111 its reverse (1111000001221), we get a palindrome (2332000002332).

The spelling of 1221000001111 in words is "one trillion, two hundred twenty-one billion, one thousand, one hundred eleven".