1218538739820 has 144 divisors (see below), whose sum is σ = 3476275619040. Its totient is φ = 318924705792.

The previous prime is 1218538739809. The next prime is 1218538739827. The reversal of 1218538739820 is 289378358121.

It is a super-2 number, since 2×1218538739820² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1218538739827) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 140558446 + ... + 140567114.

It is an arithmetic number, because the mean of its divisors is an integer number (24140802910).

Almost surely, 2^{1218538739820} is an apocalyptic number.

1218538739820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1218538739820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1738137809520).

1218538739820 is an abundant number, since it is smaller than the sum of its proper divisors (2257736879220).

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

1218538739820 is a wasteful number, since it uses less digits than its factorization.

1218538739820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9472 (or 9411 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 57.

The spelling of 1218538739820 in words is "one trillion, two hundred eighteen billion, five hundred thirty-eight million, seven hundred thirty-nine thousand, eight hundred twenty".