1981824678 has 128 divisors (see below), whose sum is σ = 4910400000. Its totient is φ = 589825152.

The previous prime is 1981824661. The next prime is 1981824679. The reversal of 1981824678 is 8764281891.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981824679) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1278648 + ... + 1280196.

It is an arithmetic number, because the mean of its divisors is an integer number (38362500).

Almost surely, 2^1981824678 is an apocalyptic number.

1981824678 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 1981824678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2455200000).

1981824678 is an abundant number, since it is smaller than the sum of its proper divisors (2928575322).

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

1981824678 is a wasteful number, since it uses less digits than its factorization.

1981824678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651 (or 1645 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 54.

The square root of 1981824678 is about 44517.6894953006. The cubic root of 1981824678 is about 1256.0928514497.

The spelling of 1981824678 in words is "one billion, nine hundred eighty-one million, eight hundred twenty-four thousand, six hundred seventy-eight".