1605443665 has 16 divisors (see below), whose sum is σ = 2317633920. Its totient is φ = 1042934400.

The previous prime is 1605443639. The next prime is 1605443681. The reversal of 1605443665 is 5663445061.

It is not a de Polignac number, because 1605443665 - 2⁹ = 1605443153 is a prime.

It is a super-2 number, since 2×1605443665² = 5154898722977264450, which contains 22 as substring.

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, 1206436 + ... + 1207765.

It is an arithmetic number, because the mean of its divisors is an integer number (144852120).

Almost surely, 2^1605443665 is an apocalyptic number.

It is an amenable number.

1605443665 is a deficient number, since it is larger than the sum of its proper divisors (712190255).

1605443665 is a wasteful number, since it uses less digits than its factorization.

1605443665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414232.

The product of its (nonzero) digits is 259200, while the sum is 40.

The square root of 1605443665 is about 40067.9880328424. The cubic root of 1605443665 is about 1170.9320415536.

The spelling of 1605443665 in words is "one billion, six hundred five million, four hundred forty-three thousand, six hundred sixty-five".