1681585920 has 540 divisors, whose sum is σ = 7020539064. Its totient is φ = 383201280.

The previous prime is 1681585903. The next prime is 1681585933. The reversal of 1681585920 is 295851861.

It is a happy number.

1681585920 is a `hidden beast` number, since 1 + 6 + 8 + 1 + 58 + 592 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (540).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 5080155 + ... + 5080485.

Almost surely, 2^1681585920 is an apocalyptic number.

1681585920 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 1681585920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3510269532).

1681585920 is an abundant number, since it is smaller than the sum of its proper divisors (5338953144).

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

1681585920 is an equidigital number, since it uses as much as digits as its factorization.

1681585920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The square root of 1681585920 is about 41007.1447433249. The cubic root of 1681585920 is about 1189.1583437283.

The spelling of 1681585920 in words is "one billion, six hundred eighty-one million, five hundred eighty-five thousand, nine hundred twenty".