1989681408 has 540 divisors, whose sum is σ = 7138017964. Its totient is φ = 547430400.

The previous prime is 1989681403. The next prime is 1989681437. The reversal of 1989681408 is 8041869891.

It can be written as a sum of positive squares in 2 ways, for example, as 160579584 + 1829101824 = 12672^2 + 42768^2 .

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 (1989681403) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 32617698 + ... + 32617758.

Almost surely, 2^1989681408 is an apocalyptic number.

1989681408 is a gapful number since it is divisible by the number (18) 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 1989681408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3569008982).

1989681408 is an abundant number, since it is smaller than the sum of its proper divisors (5148336556).

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

1989681408 is a wasteful number, since it uses less digits than its factorization.

1989681408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 54.

The square root of 1989681408 is about 44605.8449981614. The cubic root of 1989681408 is about 1257.7505442995.

The spelling of 1989681408 in words is "one billion, nine hundred eighty-nine million, six hundred eighty-one thousand, four hundred eight".