1216867878 has 48 divisors (see below), whose sum is σ = 2662523136. Its totient is φ = 401646960.

The previous prime is 1216867859. The next prime is 1216867913. The reversal of 1216867878 is 8787686121.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 994375 + ... + 995597.

It is an arithmetic number, because the mean of its divisors is an integer number (55469232).

Almost surely, 2^1216867878 is an apocalyptic number.

1216867878 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1216867878 is an abundant number, since it is smaller than the sum of its proper divisors (1445655258).

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

1216867878 is a wasteful number, since it uses less digits than its factorization.

1216867878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1729 (or 1726 counting only the distinct ones).

The product of its digits is 1806336, while the sum is 54.

The square root of 1216867878 is about 34883.6333830064. The cubic root of 1216867878 is about 1067.6145297029.

The spelling of 1216867878 in words is "one billion, two hundred sixteen million, eight hundred sixty-seven thousand, eight hundred seventy-eight".