1221012105 has 48 divisors (see below), whose sum is σ = 2070567360. Its totient is φ = 614330496.

The previous prime is 1221012083. The next prime is 1221012119. The reversal of 1221012105 is 5012101221.

It is not a de Polignac number, because 1221012105 - 2⁵ = 1221012073 is a prime.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2398591 + ... + 2399099.

It is an arithmetic number, because the mean of its divisors is an integer number (43136820).

Almost surely, 2^1221012105 is an apocalyptic number.

1221012105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221012105 is a deficient number, since it is larger than the sum of its proper divisors (849555255).

1221012105 is a wasteful number, since it uses less digits than its factorization.

1221012105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998 (or 979 counting only the distinct ones).

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

The square root of 1221012105 is about 34942.9836304801. The cubic root of 1221012105 is about 1068.8251305209.

Adding to 1221012105 its reverse (5012101221), we get a palindrome (6233113326).

The spelling of 1221012105 in words is "one billion, two hundred twenty-one million, twelve thousand, one hundred five".