1681644240 has 200 divisors, whose sum is σ = 5885769120. Its totient is φ = 444973824.

The previous prime is 1681644221. The next prime is 1681644253. The reversal of 1681644240 is 424461861.

It is a happy number.

1681644240 is a `hidden beast` number, since 1 + 6 + 8 + 1 + 644 + 2 + 4 + 0 = 666.

1681644240 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1681644195 and 1681644204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 899787 + ... + 901653.

Almost surely, 2^1681644240 is an apocalyptic number.

1681644240 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 1681644240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2942884560).

1681644240 is an abundant number, since it is smaller than the sum of its proper divisors (4204124880).

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

1681644240 is a wasteful number, since it uses less digits than its factorization.

1681644240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2031 (or 2016 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 1681644240 is about 41007.8558327548. The cubic root of 1681644240 is about 1189.1720908527.

The spelling of 1681644240 in words is "one billion, six hundred eighty-one million, six hundred forty-four thousand, two hundred forty".