1981985418 has 144 divisors (see below), whose sum is σ = 5314926240. Its totient is φ = 530712000.

The previous prime is 1981985413. The next prime is 1981985459. The reversal of 1981985418 is 8145891891.

1981985418 is a `hidden beast` number, since 1 + 9 + 8 + 1 + 98 + 541 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (1981985413) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1691973 + ... + 1693143.

It is an arithmetic number, because the mean of its divisors is an integer number (36909210).

Almost surely, 2^1981985418 is an apocalyptic number.

1981985418 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1981985418, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2657463120).

1981985418 is an abundant number, since it is smaller than the sum of its proper divisors (3332940822).

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

1981985418 is a wasteful number, since it uses less digits than its factorization.

1981985418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313 (or 1303 counting only the distinct ones).

The product of its digits is 829440, while the sum is 54.

The square root of 1981985418 is about 44519.4948084544. The cubic root of 1981985418 is about 1256.1268098701.

The spelling of 1981985418 in words is "one billion, nine hundred eighty-one million, nine hundred eighty-five thousand, four hundred eighteen".