1605606440 has 16 divisors (see below), whose sum is σ = 3612614580. Its totient is φ = 642242560.

The previous prime is 1605606439. The next prime is 1605606461. The reversal of 1605606440 is 446065061.

It can be written as a sum of positive squares in 2 ways, for example, as 1302776836 + 302829604 = 36094^2 + 17402^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1605606397 and 1605606406.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20070041 + ... + 20070120.

Almost surely, 2^1605606440 is an apocalyptic number.

1605606440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1605606440 is an abundant number, since it is smaller than the sum of its proper divisors (2007008140).

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

1605606440 is a wasteful number, since it uses less digits than its factorization.

1605606440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40140172 (or 40140168 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 1605606440 is about 40070.0192163667. The cubic root of 1605606440 is about 1170.9716135893.

The spelling of 1605606440 in words is "one billion, six hundred five million, six hundred six thousand, four hundred forty".