1221000111 has 24 divisors (see below), whose sum is σ = 1813928480. Its totient is φ = 790865856.

The previous prime is 1221000107. The next prime is 1221000113. The reversal of 1221000111 is 1110001221.

It is a happy number.

It is not a de Polignac number, because 1221000111 - 2² = 1221000107 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221000093 and 1221000102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221000113) 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, 273846 + ... + 278268.

Almost surely, 2^1221000111 is an apocalyptic number.

1221000111 is a deficient number, since it is larger than the sum of its proper divisors (592928369).

1221000111 is a wasteful number, since it uses less digits than its factorization.

1221000111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5295 (or 5292 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1221000111 is about 34942.8120076218. The cubic root of 1221000111 is about 1068.8216308202.

Adding to 1221000111 its reverse (1110001221), we get a palindrome (2331001332).

The spelling of 1221000111 in words is "one billion, two hundred twenty-one million, one hundred eleven", and thus it is an aban number.