1216451205 has 24 divisors (see below), whose sum is σ = 2110249440. Its totient is φ = 648240480.

The previous prime is 1216451189. The next prime is 1216451207. The reversal of 1216451205 is 5021546121.

1216451205 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 451 + 205 = 666.

It is not a de Polignac number, because 1216451205 - 2⁴ = 1216451189 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216451207) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47626 + ... + 68564.

It is an arithmetic number, because the mean of its divisors is an integer number (87927060).

Almost surely, 2^1216451205 is an apocalyptic number.

1216451205 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216451205 is a deficient number, since it is larger than the sum of its proper divisors (893798235).

1216451205 is a wasteful number, since it uses less digits than its factorization.

1216451205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22241 (or 22238 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 1216451205 is about 34877.6605436775. The cubic root of 1216451205 is about 1067.4926602870.

Adding to 1216451205 its reverse (5021546121), we get a palindrome (6237997326).

The spelling of 1216451205 in words is "one billion, two hundred sixteen million, four hundred fifty-one thousand, two hundred five".