1605042640 has 40 divisors (see below), whose sum is σ = 3735330120. Its totient is φ = 641396736.

The previous prime is 1605042599. The next prime is 1605042661. The reversal of 1605042640 is 462405061.

It can be written as a sum of positive squares in 4 ways, for example, as 429649984 + 1175392656 = 20728^2 + 34284^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 1605042599 and 1605042608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78616 + ... + 96904.

It is an arithmetic number, because the mean of its divisors is an integer number (93383253).

Almost surely, 2^1605042640 is an apocalyptic number.

1605042640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1605042640 is an abundant number, since it is smaller than the sum of its proper divisors (2130287480).

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

1605042640 is a wasteful number, since it uses less digits than its factorization.

1605042640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19399 (or 19393 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 1605042640 is about 40062.9834136201. The cubic root of 1605042640 is about 1170.8345374314.

The spelling of 1605042640 in words is "one billion, six hundred five million, forty-two thousand, six hundred forty".