1218666856 has 32 divisors (see below), whose sum is σ = 2494346400. Its totient is φ = 553579840.

The previous prime is 1218666853. The next prime is 1218666887. The reversal of 1218666856 is 6586668121.

It is not an unprimeable number, because it can be changed into a prime (1218666853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170115 + ... + 177133.

It is an arithmetic number, because the mean of its divisors is an integer number (77948325).

Almost surely, 2^1218666856 is an apocalyptic number.

It is an amenable number.

1218666856 is an abundant number, since it is smaller than the sum of its proper divisors (1275679544).

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

1218666856 is a wasteful number, since it uses less digits than its factorization.

1218666856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9009 (or 9005 counting only the distinct ones).

The product of its digits is 829440, while the sum is 49.

The square root of 1218666856 is about 34909.4092760104. The cubic root of 1218666856 is about 1068.1403795519.

The spelling of 1218666856 in words is "one billion, two hundred eighteen million, six hundred sixty-six thousand, eight hundred fifty-six".