1605993220 has 48 divisors (see below), whose sum is σ = 3648149568. Its totient is φ = 590348160.

The previous prime is 1605993209. The next prime is 1605993253. The reversal of 1605993220 is 223995061.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1605993220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45415 + ... + 72625.

It is an arithmetic number, because the mean of its divisors is an integer number (76003116).

Almost surely, 2^1605993220 is an apocalyptic number.

1605993220 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 1605993220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1824074784).

1605993220 is an abundant number, since it is smaller than the sum of its proper divisors (2042156348).

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

1605993220 is a wasteful number, since it uses less digits than its factorization.

1605993220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27460 (or 27458 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 1605993220 is about 40074.8452273992. The cubic root of 1605993220 is about 1171.0656324860.

The spelling of 1605993220 in words is "one billion, six hundred five million, nine hundred ninety-three thousand, two hundred twenty".