1216639287378 has 48 divisors (see below), whose sum is σ = 2676490371360. Its totient is φ = 399330062208.

The previous prime is 1216639287377. The next prime is 1216639287379. The reversal of 1216639287378 is 8737829366121.

1216639287378 is a `hidden beast` number, since 1 + 2 + 166 + 392 + 87 + 3 + 7 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (1216639287377) and next prime (1216639287379).

It is a super-2 number, since 2×1216639287378² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1216639287373) 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, 2760426 + ... + 3170682.

It is an arithmetic number, because the mean of its divisors is an integer number (55760216070).

Almost surely, 2^{1216639287378} is an apocalyptic number.

1216639287378 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1216639287378 is an abundant number, since it is smaller than the sum of its proper divisors (1459851083982).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216639287378 is a wasteful number, since it uses less digits than its factorization.

1216639287378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 412791 (or 412788 counting only the distinct ones).

The product of its digits is 36578304, while the sum is 63.

The spelling of 1216639287378 in words is "one trillion, two hundred sixteen billion, six hundred thirty-nine million, two hundred eighty-seven thousand, three hundred seventy-eight".