1216055985 has 32 divisors (see below), whose sum is σ = 2131194240. Its totient is φ = 589360128.

The previous prime is 1216055983. The next prime is 1216055987. The reversal of 1216055985 is 5895506121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1216055983) and next prime (1216055987).

It is not a de Polignac number, because 1216055985 - 2¹ = 1216055983 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1216055983) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74827 + ... + 89616.

It is an arithmetic number, because the mean of its divisors is an integer number (66599820).

Almost surely, 2^1216055985 is an apocalyptic number.

1216055985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216055985 is a deficient number, since it is larger than the sum of its proper divisors (915138255).

1216055985 is a wasteful number, since it uses less digits than its factorization.

1216055985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164497.

The product of its (nonzero) digits is 108000, while the sum is 42.

The square root of 1216055985 is about 34871.9942790773. The cubic root of 1216055985 is about 1067.3770397710.

The spelling of 1216055985 in words is "one billion, two hundred sixteen million, fifty-five thousand, nine hundred eighty-five".