1605985920 has 1024 divisors, whose sum is σ = 7614259200. Its totient is φ = 309657600.

The previous prime is 1605985897. The next prime is 1605985981. The reversal of 1605985920 is 295895061.

1605985920 is a `hidden beast` number, since 1 + 6 + 0 + 59 + 8 + 592 + 0 = 666.

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 127 ways as a sum of consecutive naturals, for example, 22619485 + ... + 22619555.

It is an arithmetic number, because the mean of its divisors is an integer number (7435800).

Almost surely, 2^1605985920 is an apocalyptic number.

1605985920 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 1605985920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3807129600).

1605985920 is an abundant number, since it is smaller than the sum of its proper divisors (6008273280).

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

1605985920 is a wasteful number, since it uses less digits than its factorization.

1605985920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134 (or 116 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The square root of 1605985920 is about 40074.7541477175. The cubic root of 1605985920 is about 1171.0638581339.

1605985920 divided by its sum of digits (45) gives a triangular number (35688576 = T₈₄₄₈).

The spelling of 1605985920 in words is "one billion, six hundred five million, nine hundred eighty-five thousand, nine hundred twenty".