1218311660 has 12 divisors (see below), whose sum is σ = 2558454528. Its totient is φ = 487324656.

The previous prime is 1218311603. The next prime is 1218311669. The reversal of 1218311660 is 661138121.

It is not an unprimeable number, because it can be changed into a prime (1218311669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30457772 + ... + 30457811.

It is an arithmetic number, because the mean of its divisors is an integer number (213204544).

Almost surely, 2^1218311660 is an apocalyptic number.

1218311660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1218311660 is an abundant number, since it is smaller than the sum of its proper divisors (1340142868).

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

1218311660 is a wasteful number, since it uses less digits than its factorization.

1218311660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60915592 (or 60915590 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 1218311660 is about 34904.3215089479. The cubic root of 1218311660 is about 1068.0365950886.

Adding to 1218311660 its reverse (661138121), we get a palindrome (1879449781).

The spelling of 1218311660 in words is "one billion, two hundred eighteen million, three hundred eleven thousand, six hundred sixty".