1221000011 has 16 divisors (see below), whose sum is σ = 1588474368. Its totient is φ = 910060800.

The previous prime is 1220999999. The next prime is 1221000017. The reversal of 1221000011 is 1100001221.

1221000011 = T₅₅₉₃ + T₅₅₉₄ + ... + T₅₆₆₉.

It is not a de Polignac number, because 1221000011 - 2¹⁸ = 1220737867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221000017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 342950 + ... + 346491.

It is an arithmetic number, because the mean of its divisors is an integer number (99279648).

Almost surely, 2^1221000011 is an apocalyptic number.

1221000011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221000011 is a deficient number, since it is larger than the sum of its proper divisors (367474357).

1221000011 is a wasteful number, since it uses less digits than its factorization.

1221000011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689482.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 1221000011 is about 34942.8105767123. The cubic root of 1221000011 is about 1068.8216016413.

Adding to 1221000011 its reverse (1100001221), we get a palindrome (2321001232).

The spelling of 1221000011 in words is "one billion, two hundred twenty-one million, eleven", and thus it is an aban number.