1216042305 has 16 divisors (see below), whose sum is σ = 1953072000. Its totient is φ = 646087808.

The previous prime is 1216042273. The next prime is 1216042307. The reversal of 1216042305 is 5032406121.

It is a cyclic number.

It is not a de Polignac number, because 1216042305 - 2⁵ = 1216042273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1216042307) 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, 150180 + ... + 158069.

It is an arithmetic number, because the mean of its divisors is an integer number (122067000).

Almost surely, 2^1216042305 is an apocalyptic number.

1216042305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216042305 is a deficient number, since it is larger than the sum of its proper divisors (737029695).

1216042305 is a wasteful number, since it uses less digits than its factorization.

1216042305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308520.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 1216042305 is about 34871.7981325885. The cubic root of 1216042305 is about 1067.3730372763.

Adding to 1216042305 its reverse (5032406121), we get a palindrome (6248448426).

The spelling of 1216042305 in words is "one billion, two hundred sixteen million, forty-two thousand, three hundred five".