1221021105 has 16 divisors (see below), whose sum is σ = 1954247424. Its totient is φ = 651006720.

The previous prime is 1221021103. The next prime is 1221021119. The reversal of 1221021105 is 5011201221.

It is not a de Polignac number, because 1221021105 - 2¹ = 1221021103 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (1221021103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44985 + ... + 66825.

It is an arithmetic number, because the mean of its divisors is an integer number (122140464).

Almost surely, 2^1221021105 is an apocalyptic number.

1221021105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221021105 is a deficient number, since it is larger than the sum of its proper divisors (733226319).

1221021105 is a wasteful number, since it uses less digits than its factorization.

1221021105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25576.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 1221021105 is about 34943.1124114610. The cubic root of 1221021105 is about 1068.8277565943.

Adding to 1221021105 its reverse (5011201221), we get a palindrome (6232222326).

The spelling of 1221021105 in words is "one billion, two hundred twenty-one million, twenty-one thousand, one hundred five".