1605609840 has 80 divisors (see below), whose sum is σ = 5033383200. Its totient is φ = 423346176.

The previous prime is 1605609823. The next prime is 1605609847. The reversal of 1605609840 is 489065061.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605609847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16225 + ... + 58944.

It is an arithmetic number, because the mean of its divisors is an integer number (62917290).

Almost surely, 2^1605609840 is an apocalyptic number.

1605609840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1605609840 is an abundant number, since it is smaller than the sum of its proper divisors (3427773360).

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

1605609840 is a wasteful number, since it uses less digits than its factorization.

1605609840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75274 (or 75268 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 1605609840 is about 40070.0616420789. The cubic root of 1605609840 is about 1170.9724401307.

The spelling of 1605609840 in words is "one billion, six hundred five million, six hundred nine thousand, eight hundred forty".