1216056105 has 64 divisors (see below), whose sum is σ = 2416055040. Its totient is φ = 575193600.

The previous prime is 1216056047. The next prime is 1216056109. The reversal of 1216056105 is 5016506121.

It is a happy number.

It is not a de Polignac number, because 1216056105 - 2⁶ = 1216056041 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1216056109) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 50899 + ... + 70871.

It is an arithmetic number, because the mean of its divisors is an integer number (37750860).

Almost surely, 2^1216056105 is an apocalyptic number.

1216056105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216056105 is a deficient number, since it is larger than the sum of its proper divisors (1199998935).

1216056105 is a wasteful number, since it uses less digits than its factorization.

1216056105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20039 (or 20033 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 1216056105 is about 34871.9959996557. The cubic root of 1216056105 is about 1067.3770748805.

It can be divided in two parts, 12160 and 56105, that added together give a triangular number (68265 = T₃₆₉).

The spelling of 1216056105 in words is "one billion, two hundred sixteen million, fifty-six thousand, one hundred five".