1218187940 has 12 divisors (see below), whose sum is σ = 2558194716. Its totient is φ = 487275168.

The previous prime is 1218187837. The next prime is 1218187951. The reversal of 1218187940 is 497818121.

It can be written as a sum of positive squares in 2 ways, for example, as 379158784 + 839029156 = 19472^2 + 28966^2 .

It is a super-2 number, since 2×1218187940² = 2967963714322887200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30454679 + ... + 30454718.

It is an arithmetic number, because the mean of its divisors is an integer number (213182893).

Almost surely, 2^1218187940 is an apocalyptic number.

1218187940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1218187940 is an abundant number, since it is smaller than the sum of its proper divisors (1340006776).

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

1218187940 is a wasteful number, since it uses less digits than its factorization.

1218187940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60909406 (or 60909404 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 41.

The square root of 1218187940 is about 34902.5491905677. The cubic root of 1218187940 is about 1068.0004406943. Note that the first 3 decimals are identical.

The spelling of 1218187940 in words is "one billion, two hundred eighteen million, one hundred eighty-seven thousand, nine hundred forty".