1681759440 has 120 divisors (see below), whose sum is σ = 5663729760. Its totient is φ = 447213312.

The previous prime is 1681759439. The next prime is 1681759441. The reversal of 1681759440 is 449571861.

1681759440 is a `hidden beast` number, since 1 + 6 + 8 + 17 + 594 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (1681759439) and next prime (1681759441).

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×1681759440² = 5656629628058227200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1681759441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 269799 + ... + 275961.

It is an arithmetic number, because the mean of its divisors is an integer number (47197748).

Almost surely, 2^1681759440 is an apocalyptic number.

1681759440 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 1681759440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2831864880).

1681759440 is an abundant number, since it is smaller than the sum of its proper divisors (3981970320).

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

1681759440 is a wasteful number, since it uses less digits than its factorization.

1681759440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6561 (or 6552 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 1681759440 is about 41009.2604176179. The cubic root of 1681759440 is about 1189.1992447326.

The spelling of 1681759440 in words is "one billion, six hundred eighty-one million, seven hundred fifty-nine thousand, four hundred forty".